From: Mike Bayer Date: Tue, 5 Apr 2022 23:00:19 +0000 (-0400) Subject: use code generation for scoped_session X-Git-Tag: rel_2_0_0b1~357 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=98eae4e181cb2d1bbc67ec834bfad29dcba7f461;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git use code generation for scoped_session our decorator thing generates code in any case, so point it at the file itself to generate real code for the blocks rather than doing things dynamically. this will allow typing tools to have no problem whatsoever and we also reduce import time overhead. file size will be a lot bigger though, shrugs. syntax / dupe method / etc. checking will be accomplished by our existing linting / typing / formatting tools. As we are also using "from __future__ import annotations", we also no longer have to apply quotes to generated annotations. Change-Id: I20962cb65bda63ff0fb67357ab346e9b1ef4f108 --- diff --git a/MANIFEST.in b/MANIFEST.in index eb447a0bd0..7a272fe6b4 100644 --- a/MANIFEST.in +++ b/MANIFEST.in @@ -4,6 +4,7 @@ recursive-include doc *.html *.css *.txt *.js *.png *.py Makefile *.rst *.sty recursive-include examples *.py *.xml recursive-include test *.py *.dat *.testpatch +recursive-include tools *.py # for some reason in some environments stale Cython .c files # are being pulled in, these should never be in a dist diff --git a/lib/sqlalchemy/engine/base.py b/lib/sqlalchemy/engine/base.py index f3d30860ad..5c446a91dc 100644 --- a/lib/sqlalchemy/engine/base.py +++ b/lib/sqlalchemy/engine/base.py @@ -2672,14 +2672,18 @@ class Engine( @property def name(self) -> str: """String name of the :class:`~sqlalchemy.engine.interfaces.Dialect` - in use by this :class:`Engine`.""" + in use by this :class:`Engine`. + + """ return self.dialect.name @property def driver(self) -> str: """Driver name of the :class:`~sqlalchemy.engine.interfaces.Dialect` - in use by this :class:`Engine`.""" + in use by this :class:`Engine`. + + """ return self.dialect.driver diff --git a/lib/sqlalchemy/ext/asyncio/engine.py b/lib/sqlalchemy/ext/asyncio/engine.py index fcf3b974db..3b54405c15 100644 --- a/lib/sqlalchemy/ext/asyncio/engine.py +++ b/lib/sqlalchemy/ext/asyncio/engine.py @@ -4,6 +4,10 @@ # # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php +from __future__ import annotations + +from typing import Any + from . import exc as async_exc from .base import ProxyComparable from .base import StartableContext @@ -72,7 +76,7 @@ class AsyncConnectable: @util.create_proxy_methods( Connection, - ":class:`_future.Connection`", + ":class:`_engine.Connection`", ":class:`_asyncio.AsyncConnection`", classmethods=[], methods=[], @@ -125,6 +129,7 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable): .. seealso:: :ref:`asyncio_events` + """ sync_engine: Engine @@ -137,6 +142,7 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable): .. seealso:: :ref:`asyncio_events` + """ @classmethod @@ -552,10 +558,100 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable): async def __aexit__(self, type_, value, traceback): await self.close() + # START PROXY METHODS AsyncConnection + + # code within this block is **programmatically, + # statically generated** by tools/generate_proxy_methods.py + + @property + def closed(self) -> Any: + r"""Return True if this connection is closed. + + .. container:: class_bases + + Proxied for the :class:`_engine.Connection` class + on behalf of the :class:`_asyncio.AsyncConnection` class. + + """ # noqa: E501 + + return self._proxied.closed + + @property + def invalidated(self) -> Any: + r"""Return True if this connection was invalidated. + + .. container:: class_bases + + Proxied for the :class:`_engine.Connection` class + on behalf of the :class:`_asyncio.AsyncConnection` class. + + This does not indicate whether or not the connection was + invalidated at the pool level, however + + + """ # noqa: E501 + + return self._proxied.invalidated + + @property + def dialect(self) -> Any: + r"""Proxy for the :attr:`_engine.Connection.dialect` attribute + on behalf of the :class:`_asyncio.AsyncConnection` class. + + """ # noqa: E501 + + return self._proxied.dialect + + @dialect.setter + def dialect(self, attr: Any) -> None: + self._proxied.dialect = attr + + @property + def default_isolation_level(self) -> Any: + r"""The default isolation level assigned to this + :class:`_engine.Connection`. + + .. container:: class_bases + + Proxied for the :class:`_engine.Connection` class + on behalf of the :class:`_asyncio.AsyncConnection` class. + + This is the isolation level setting that the + :class:`_engine.Connection` + has when first procured via the :meth:`_engine.Engine.connect` method. + This level stays in place until the + :paramref:`.Connection.execution_options.isolation_level` is used + to change the setting on a per-:class:`_engine.Connection` basis. + + Unlike :meth:`_engine.Connection.get_isolation_level`, + this attribute is set + ahead of time from the first connection procured by the dialect, + so SQL query is not invoked when this accessor is called. + + .. versionadded:: 0.9.9 + + .. seealso:: + + :meth:`_engine.Connection.get_isolation_level` + - view current level + + :paramref:`_sa.create_engine.isolation_level` + - set per :class:`_engine.Engine` isolation level + + :paramref:`.Connection.execution_options.isolation_level` + - set per :class:`_engine.Connection` isolation level + + + """ # noqa: E501 + + return self._proxied.default_isolation_level + + # END PROXY METHODS AsyncConnection + @util.create_proxy_methods( Engine, - ":class:`_future.Engine`", + ":class:`_engine.Engine`", ":class:`_asyncio.AsyncEngine`", classmethods=[], methods=[ @@ -701,6 +797,181 @@ class AsyncEngine(ProxyComparable, AsyncConnectable): return await greenlet_spawn(self.sync_engine.dispose) + # START PROXY METHODS AsyncEngine + + # code within this block is **programmatically, + # statically generated** by tools/generate_proxy_methods.py + + def clear_compiled_cache(self) -> None: + r"""Clear the compiled cache associated with the dialect. + + .. container:: class_bases + + Proxied for the :class:`_engine.Engine` class on + behalf of the :class:`_asyncio.AsyncEngine` class. + + This applies **only** to the built-in cache that is established + via the :paramref:`_engine.create_engine.query_cache_size` parameter. + It will not impact any dictionary caches that were passed via the + :paramref:`.Connection.execution_options.query_cache` parameter. + + .. versionadded:: 1.4 + + + """ # noqa: E501 + + return self._proxied.clear_compiled_cache() + + def update_execution_options(self, **opt: Any) -> None: + r"""Update the default execution_options dictionary + of this :class:`_engine.Engine`. + + .. container:: class_bases + + Proxied for the :class:`_engine.Engine` class on + behalf of the :class:`_asyncio.AsyncEngine` class. + + The given keys/values in \**opt are added to the + default execution options that will be used for + all connections. The initial contents of this dictionary + can be sent via the ``execution_options`` parameter + to :func:`_sa.create_engine`. + + .. seealso:: + + :meth:`_engine.Connection.execution_options` + + :meth:`_engine.Engine.execution_options` + + + """ # noqa: E501 + + return self._proxied.update_execution_options(**opt) + + def get_execution_options(self) -> _ExecuteOptions: + r"""Get the non-SQL options which will take effect during execution. + + .. container:: class_bases + + Proxied for the :class:`_engine.Engine` class on + behalf of the :class:`_asyncio.AsyncEngine` class. + + .. versionadded: 1.3 + + .. seealso:: + + :meth:`_engine.Engine.execution_options` + + """ # noqa: E501 + + return self._proxied.get_execution_options() + + @property + def url(self) -> URL: + r"""Proxy for the :attr:`_engine.Engine.url` attribute + on behalf of the :class:`_asyncio.AsyncEngine` class. + + """ # noqa: E501 + + return self._proxied.url + + @url.setter + def url(self, attr: URL) -> None: + self._proxied.url = attr + + @property + def pool(self) -> Pool: + r"""Proxy for the :attr:`_engine.Engine.pool` attribute + on behalf of the :class:`_asyncio.AsyncEngine` class. + + """ # noqa: E501 + + return self._proxied.pool + + @pool.setter + def pool(self, attr: Pool) -> None: + self._proxied.pool = attr + + @property + def dialect(self) -> Dialect: + r"""Proxy for the :attr:`_engine.Engine.dialect` attribute + on behalf of the :class:`_asyncio.AsyncEngine` class. + + """ # noqa: E501 + + return self._proxied.dialect + + @dialect.setter + def dialect(self, attr: Dialect) -> None: + self._proxied.dialect = attr + + @property + def engine(self) -> Any: + r""".. container:: class_bases + + Proxied for the :class:`_engine.Engine` class + on behalf of the :class:`_asyncio.AsyncEngine` class. + + + """ # noqa: E501 + + return self._proxied.engine + + @property + def name(self) -> Any: + r"""String name of the :class:`~sqlalchemy.engine.interfaces.Dialect` + in use by this :class:`Engine`. + + .. container:: class_bases + + Proxied for the :class:`_engine.Engine` class + on behalf of the :class:`_asyncio.AsyncEngine` class. + + + """ # noqa: E501 + + return self._proxied.name + + @property + def driver(self) -> Any: + r"""Driver name of the :class:`~sqlalchemy.engine.interfaces.Dialect` + in use by this :class:`Engine`. + + .. container:: class_bases + + Proxied for the :class:`_engine.Engine` class + on behalf of the :class:`_asyncio.AsyncEngine` class. + + + """ # noqa: E501 + + return self._proxied.driver + + @property + def echo(self) -> Any: + r"""When ``True``, enable log output for this element. + + .. container:: class_bases + + Proxied for the :class:`_engine.Engine` class + on behalf of the :class:`_asyncio.AsyncEngine` class. + + This has the effect of setting the Python logging level for the namespace + of this element's class and object reference. A value of boolean ``True`` + indicates that the loglevel ``logging.INFO`` will be set for the logger, + whereas the string value ``debug`` will set the loglevel to + ``logging.DEBUG``. + + """ # noqa: E501 + + return self._proxied.echo + + @echo.setter + def echo(self, attr: Any) -> None: + self._proxied.echo = attr + + # END PROXY METHODS AsyncEngine + class AsyncTransaction(ProxyComparable, StartableContext): """An asyncio proxy for a :class:`_engine.Transaction`.""" diff --git a/lib/sqlalchemy/ext/asyncio/scoping.py b/lib/sqlalchemy/ext/asyncio/scoping.py index 8eca8c5248..cc57251255 100644 --- a/lib/sqlalchemy/ext/asyncio/scoping.py +++ b/lib/sqlalchemy/ext/asyncio/scoping.py @@ -5,7 +5,12 @@ # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php +from __future__ import annotations + +from typing import Any + from .session import AsyncSession +from ... import util from ...orm.scoping import ScopedSessionMixin from ...util import create_proxy_methods from ...util import ScopedRegistry @@ -105,3 +110,1119 @@ class async_scoped_session(ScopedSessionMixin): if self.registry.has(): await self.registry().close() self.registry.clear() + + # START PROXY METHODS async_scoped_session + + # code within this block is **programmatically, + # statically generated** by tools/generate_proxy_methods.py + + def __contains__(self, instance): + r"""Return True if the instance is associated with this session. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + The instance may be pending or persistent within the Session for a + result of True. + + + + """ # noqa: E501 + + return self._proxied.__contains__(instance) + + def __iter__(self): + r"""Iterate over all pending or persistent instances within this + Session. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + """ + + return self._proxied.__iter__() + + def add(self, instance: Any, _warn: bool = True) -> None: + r"""Place an object in the ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + Its state will be persisted to the database on the next flush + operation. + + Repeated calls to ``add()`` will be ignored. The opposite of ``add()`` + is ``expunge()``. + + + + """ # noqa: E501 + + return self._proxied.add(instance, _warn=_warn) + + def add_all(self, instances): + r"""Add the given collection of instances to this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + + """ # noqa: E501 + + return self._proxied.add_all(instances) + + def begin(self): + r"""Return an :class:`_asyncio.AsyncSessionTransaction` object. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + The underlying :class:`_orm.Session` will perform the + "begin" action when the :class:`_asyncio.AsyncSessionTransaction` + object is entered:: + + async with async_session.begin(): + # .. ORM transaction is begun + + Note that database IO will not normally occur when the session-level + transaction is begun, as database transactions begin on an + on-demand basis. However, the begin block is async to accommodate + for a :meth:`_orm.SessionEvents.after_transaction_create` + event hook that may perform IO. + + For a general description of ORM begin, see + :meth:`_orm.Session.begin`. + + + """ # noqa: E501 + + return self._proxied.begin() + + def begin_nested(self): + r"""Return an :class:`_asyncio.AsyncSessionTransaction` object + which will begin a "nested" transaction, e.g. SAVEPOINT. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + Behavior is the same as that of :meth:`_asyncio.AsyncSession.begin`. + + For a general description of ORM begin nested, see + :meth:`_orm.Session.begin_nested`. + + + """ # noqa: E501 + + return self._proxied.begin_nested() + + async def close(self): + r"""Close out the transactional resources and ORM objects used by this + :class:`_asyncio.AsyncSession`. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + This expunges all ORM objects associated with this + :class:`_asyncio.AsyncSession`, ends any transaction in progress and + :term:`releases` any :class:`_asyncio.AsyncConnection` objects which + this :class:`_asyncio.AsyncSession` itself has checked out from + associated :class:`_asyncio.AsyncEngine` objects. The operation then + leaves the :class:`_asyncio.AsyncSession` in a state which it may be + used again. + + .. tip:: + + The :meth:`_asyncio.AsyncSession.close` method **does not prevent + the Session from being used again**. The + :class:`_asyncio.AsyncSession` itself does not actually have a + distinct "closed" state; it merely means the + :class:`_asyncio.AsyncSession` will release all database + connections and ORM objects. + + + .. seealso:: + + :ref:`session_closing` - detail on the semantics of + :meth:`_asyncio.AsyncSession.close` + + + """ # noqa: E501 + + return await self._proxied.close() + + async def commit(self): + r"""Commit the current transaction in progress. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + """ # noqa: E501 + + return await self._proxied.commit() + + async def connection(self, **kw): + r"""Return a :class:`_asyncio.AsyncConnection` object corresponding to + this :class:`.Session` object's transactional state. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + This method may also be used to establish execution options for the + database connection used by the current transaction. + + .. versionadded:: 1.4.24 Added **kw arguments which are passed through + to the underlying :meth:`_orm.Session.connection` method. + + .. seealso:: + + :meth:`_orm.Session.connection` - main documentation for + "connection" + + + """ # noqa: E501 + + return await self._proxied.connection(**kw) + + async def delete(self, instance): + r"""Mark an instance as deleted. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + The database delete operation occurs upon ``flush()``. + + As this operation may need to cascade along unloaded relationships, + it is awaitable to allow for those queries to take place. + + .. seealso:: + + :meth:`_orm.Session.delete` - main documentation for delete + + + """ # noqa: E501 + + return await self._proxied.delete(instance) + + async def execute( + self, + statement, + params=None, + execution_options=util.EMPTY_DICT, + bind_arguments=None, + **kw, + ): + r"""Execute a statement and return a buffered + :class:`_engine.Result` object. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. seealso:: + + :meth:`_orm.Session.execute` - main documentation for execute + + + """ # noqa: E501 + + return await self._proxied.execute( + statement, + params=params, + execution_options=execution_options, + bind_arguments=bind_arguments, + **kw, + ) + + def expire(self, instance, attribute_names=None): + r"""Expire the attributes on an instance. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + Marks the attributes of an instance as out of date. When an expired + attribute is next accessed, a query will be issued to the + :class:`.Session` object's current transactional context in order to + load all expired attributes for the given instance. Note that + a highly isolated transaction will return the same values as were + previously read in that same transaction, regardless of changes + in database state outside of that transaction. + + To expire all objects in the :class:`.Session` simultaneously, + use :meth:`Session.expire_all`. + + The :class:`.Session` object's default behavior is to + expire all state whenever the :meth:`Session.rollback` + or :meth:`Session.commit` methods are called, so that new + state can be loaded for the new transaction. For this reason, + calling :meth:`Session.expire` only makes sense for the specific + case that a non-ORM SQL statement was emitted in the current + transaction. + + :param instance: The instance to be refreshed. + :param attribute_names: optional list of string attribute names + indicating a subset of attributes to be expired. + + .. seealso:: + + :ref:`session_expire` - introductory material + + :meth:`.Session.expire` + + :meth:`.Session.refresh` + + :meth:`_orm.Query.populate_existing` + + + + """ # noqa: E501 + + return self._proxied.expire(instance, attribute_names=attribute_names) + + def expire_all(self): + r"""Expires all persistent instances within this Session. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + When any attributes on a persistent instance is next accessed, + a query will be issued using the + :class:`.Session` object's current transactional context in order to + load all expired attributes for the given instance. Note that + a highly isolated transaction will return the same values as were + previously read in that same transaction, regardless of changes + in database state outside of that transaction. + + To expire individual objects and individual attributes + on those objects, use :meth:`Session.expire`. + + The :class:`.Session` object's default behavior is to + expire all state whenever the :meth:`Session.rollback` + or :meth:`Session.commit` methods are called, so that new + state can be loaded for the new transaction. For this reason, + calling :meth:`Session.expire_all` is not usually needed, + assuming the transaction is isolated. + + .. seealso:: + + :ref:`session_expire` - introductory material + + :meth:`.Session.expire` + + :meth:`.Session.refresh` + + :meth:`_orm.Query.populate_existing` + + + + """ # noqa: E501 + + return self._proxied.expire_all() + + def expunge(self, instance): + r"""Remove the `instance` from this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This will free all internal references to the instance. Cascading + will be applied according to the *expunge* cascade rule. + + + + """ # noqa: E501 + + return self._proxied.expunge(instance) + + def expunge_all(self): + r"""Remove all object instances from this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This is equivalent to calling ``expunge(obj)`` on all objects in this + ``Session``. + + + + """ # noqa: E501 + + return self._proxied.expunge_all() + + async def flush(self, objects=None): + r"""Flush all the object changes to the database. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. seealso:: + + :meth:`_orm.Session.flush` - main documentation for flush + + + """ # noqa: E501 + + return await self._proxied.flush(objects=objects) + + async def get( + self, + entity, + ident, + options=None, + populate_existing=False, + with_for_update=None, + identity_token=None, + ): + r"""Return an instance based on the given primary key identifier, + or ``None`` if not found. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. seealso:: + + :meth:`_orm.Session.get` - main documentation for get + + + + """ # noqa: E501 + + return await self._proxied.get( + entity, + ident, + options=options, + populate_existing=populate_existing, + with_for_update=with_for_update, + identity_token=identity_token, + ) + + def get_bind(self, mapper=None, clause=None, bind=None, **kw): + r"""Return a "bind" to which the synchronous proxied :class:`_orm.Session` + is bound. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + Unlike the :meth:`_orm.Session.get_bind` method, this method is + currently **not** used by this :class:`.AsyncSession` in any way + in order to resolve engines for requests. + + .. note:: + + This method proxies directly to the :meth:`_orm.Session.get_bind` + method, however is currently **not** useful as an override target, + in contrast to that of the :meth:`_orm.Session.get_bind` method. + The example below illustrates how to implement custom + :meth:`_orm.Session.get_bind` schemes that work with + :class:`.AsyncSession` and :class:`.AsyncEngine`. + + The pattern introduced at :ref:`session_custom_partitioning` + illustrates how to apply a custom bind-lookup scheme to a + :class:`_orm.Session` given a set of :class:`_engine.Engine` objects. + To apply a corresponding :meth:`_orm.Session.get_bind` implementation + for use with a :class:`.AsyncSession` and :class:`.AsyncEngine` + objects, continue to subclass :class:`_orm.Session` and apply it to + :class:`.AsyncSession` using + :paramref:`.AsyncSession.sync_session_class`. The inner method must + continue to return :class:`_engine.Engine` instances, which can be + acquired from a :class:`_asyncio.AsyncEngine` using the + :attr:`_asyncio.AsyncEngine.sync_engine` attribute:: + + # using example from "Custom Vertical Partitioning" + + + import random + + from sqlalchemy.ext.asyncio import AsyncSession + from sqlalchemy.ext.asyncio import create_async_engine + from sqlalchemy.orm import Session, sessionmaker + + # construct async engines w/ async drivers + engines = { + 'leader':create_async_engine("sqlite+aiosqlite:///leader.db"), + 'other':create_async_engine("sqlite+aiosqlite:///other.db"), + 'follower1':create_async_engine("sqlite+aiosqlite:///follower1.db"), + 'follower2':create_async_engine("sqlite+aiosqlite:///follower2.db"), + } + + class RoutingSession(Session): + def get_bind(self, mapper=None, clause=None, **kw): + # within get_bind(), return sync engines + if mapper and issubclass(mapper.class_, MyOtherClass): + return engines['other'].sync_engine + elif self._flushing or isinstance(clause, (Update, Delete)): + return engines['leader'].sync_engine + else: + return engines[ + random.choice(['follower1','follower2']) + ].sync_engine + + # apply to AsyncSession using sync_session_class + AsyncSessionMaker = sessionmaker( + class_=AsyncSession, + sync_session_class=RoutingSession + ) + + The :meth:`_orm.Session.get_bind` method is called in a non-asyncio, + implicitly non-blocking context in the same manner as ORM event hooks + and functions that are invoked via :meth:`.AsyncSession.run_sync`, so + routines that wish to run SQL commands inside of + :meth:`_orm.Session.get_bind` can continue to do so using + blocking-style code, which will be translated to implicitly async calls + at the point of invoking IO on the database drivers. + + + """ # noqa: E501 + + return self._proxied.get_bind( + mapper=mapper, clause=clause, bind=bind, **kw + ) + + def is_modified(self, instance, include_collections=True): + r"""Return ``True`` if the given instance has locally + modified attributes. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This method retrieves the history for each instrumented + attribute on the instance and performs a comparison of the current + value to its previously committed value, if any. + + It is in effect a more expensive and accurate + version of checking for the given instance in the + :attr:`.Session.dirty` collection; a full test for + each attribute's net "dirty" status is performed. + + E.g.:: + + return session.is_modified(someobject) + + A few caveats to this method apply: + + * Instances present in the :attr:`.Session.dirty` collection may + report ``False`` when tested with this method. This is because + the object may have received change events via attribute mutation, + thus placing it in :attr:`.Session.dirty`, but ultimately the state + is the same as that loaded from the database, resulting in no net + change here. + * Scalar attributes may not have recorded the previously set + value when a new value was applied, if the attribute was not loaded, + or was expired, at the time the new value was received - in these + cases, the attribute is assumed to have a change, even if there is + ultimately no net change against its database value. SQLAlchemy in + most cases does not need the "old" value when a set event occurs, so + it skips the expense of a SQL call if the old value isn't present, + based on the assumption that an UPDATE of the scalar value is + usually needed, and in those few cases where it isn't, is less + expensive on average than issuing a defensive SELECT. + + The "old" value is fetched unconditionally upon set only if the + attribute container has the ``active_history`` flag set to ``True``. + This flag is set typically for primary key attributes and scalar + object references that are not a simple many-to-one. To set this + flag for any arbitrary mapped column, use the ``active_history`` + argument with :func:`.column_property`. + + :param instance: mapped instance to be tested for pending changes. + :param include_collections: Indicates if multivalued collections + should be included in the operation. Setting this to ``False`` is a + way to detect only local-column based properties (i.e. scalar columns + or many-to-one foreign keys) that would result in an UPDATE for this + instance upon flush. + + + + """ # noqa: E501 + + return self._proxied.is_modified( + instance, include_collections=include_collections + ) + + async def invalidate(self): + r"""Close this Session, using connection invalidation. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + For a complete description, see :meth:`_orm.Session.invalidate`. + + """ # noqa: E501 + + return await self._proxied.invalidate() + + async def merge(self, instance, load=True, options=None): + r"""Copy the state of a given instance into a corresponding instance + within this :class:`_asyncio.AsyncSession`. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. seealso:: + + :meth:`_orm.Session.merge` - main documentation for merge + + + """ # noqa: E501 + + return await self._proxied.merge(instance, load=load, options=options) + + async def refresh( + self, instance, attribute_names=None, with_for_update=None + ): + r"""Expire and refresh the attributes on the given instance. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + A query will be issued to the database and all attributes will be + refreshed with their current database value. + + This is the async version of the :meth:`_orm.Session.refresh` method. + See that method for a complete description of all options. + + .. seealso:: + + :meth:`_orm.Session.refresh` - main documentation for refresh + + + """ # noqa: E501 + + return await self._proxied.refresh( + instance, + attribute_names=attribute_names, + with_for_update=with_for_update, + ) + + async def rollback(self): + r"""Rollback the current transaction in progress. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + """ # noqa: E501 + + return await self._proxied.rollback() + + async def scalar( + self, + statement, + params=None, + execution_options=util.EMPTY_DICT, + bind_arguments=None, + **kw, + ): + r"""Execute a statement and return a scalar result. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. seealso:: + + :meth:`_orm.Session.scalar` - main documentation for scalar + + + """ # noqa: E501 + + return await self._proxied.scalar( + statement, + params=params, + execution_options=execution_options, + bind_arguments=bind_arguments, + **kw, + ) + + async def scalars( + self, + statement, + params=None, + execution_options=util.EMPTY_DICT, + bind_arguments=None, + **kw, + ): + r"""Execute a statement and return scalar results. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + :return: a :class:`_result.ScalarResult` object + + .. versionadded:: 1.4.24 + + .. seealso:: + + :meth:`_orm.Session.scalars` - main documentation for scalars + + :meth:`_asyncio.AsyncSession.stream_scalars` - streaming version + + + """ # noqa: E501 + + return await self._proxied.scalars( + statement, + params=params, + execution_options=execution_options, + bind_arguments=bind_arguments, + **kw, + ) + + async def stream( + self, + statement, + params=None, + execution_options=util.EMPTY_DICT, + bind_arguments=None, + **kw, + ): + r"""Execute a statement and return a streaming + :class:`_asyncio.AsyncResult` object. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + + """ # noqa: E501 + + return await self._proxied.stream( + statement, + params=params, + execution_options=execution_options, + bind_arguments=bind_arguments, + **kw, + ) + + async def stream_scalars( + self, + statement, + params=None, + execution_options=util.EMPTY_DICT, + bind_arguments=None, + **kw, + ): + r"""Execute a statement and return a stream of scalar results. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + :return: an :class:`_asyncio.AsyncScalarResult` object + + .. versionadded:: 1.4.24 + + .. seealso:: + + :meth:`_orm.Session.scalars` - main documentation for scalars + + :meth:`_asyncio.AsyncSession.scalars` - non streaming version + + + """ # noqa: E501 + + return await self._proxied.stream_scalars( + statement, + params=params, + execution_options=execution_options, + bind_arguments=bind_arguments, + **kw, + ) + + @property + def bind(self) -> Any: + r"""Proxy for the :attr:`_asyncio.AsyncSession.bind` attribute + on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + """ # noqa: E501 + + return self._proxied.bind + + @bind.setter + def bind(self, attr: Any) -> None: + self._proxied.bind = attr + + @property + def dirty(self) -> Any: + r"""The set of all persistent instances considered dirty. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class + on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + E.g.:: + + some_mapped_object in session.dirty + + Instances are considered dirty when they were modified but not + deleted. + + Note that this 'dirty' calculation is 'optimistic'; most + attribute-setting or collection modification operations will + mark an instance as 'dirty' and place it in this set, even if + there is no net change to the attribute's value. At flush + time, the value of each attribute is compared to its + previously saved value, and if there's no net change, no SQL + operation will occur (this is a more expensive operation so + it's only done at flush time). + + To check if an instance has actionable net changes to its + attributes, use the :meth:`.Session.is_modified` method. + + + + """ # noqa: E501 + + return self._proxied.dirty + + @property + def deleted(self) -> Any: + r"""The set of all instances marked as 'deleted' within this ``Session`` + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class + on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + + """ # noqa: E501 + + return self._proxied.deleted + + @property + def new(self) -> Any: + r"""The set of all instances marked as 'new' within this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class + on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + + """ # noqa: E501 + + return self._proxied.new + + @property + def identity_map(self) -> Any: + r"""Proxy for the :attr:`_orm.Session.identity_map` attribute + on behalf of the :class:`_asyncio.AsyncSession` class. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class + on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + + """ # noqa: E501 + + return self._proxied.identity_map + + @identity_map.setter + def identity_map(self, attr: Any) -> None: + self._proxied.identity_map = attr + + @property + def is_active(self) -> Any: + r"""True if this :class:`.Session` not in "partial rollback" state. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class + on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + .. versionchanged:: 1.4 The :class:`_orm.Session` no longer begins + a new transaction immediately, so this attribute will be False + when the :class:`_orm.Session` is first instantiated. + + "partial rollback" state typically indicates that the flush process + of the :class:`_orm.Session` has failed, and that the + :meth:`_orm.Session.rollback` method must be emitted in order to + fully roll back the transaction. + + If this :class:`_orm.Session` is not in a transaction at all, the + :class:`_orm.Session` will autobegin when it is first used, so in this + case :attr:`_orm.Session.is_active` will return True. + + Otherwise, if this :class:`_orm.Session` is within a transaction, + and that transaction has not been rolled back internally, the + :attr:`_orm.Session.is_active` will also return True. + + .. seealso:: + + :ref:`faq_session_rollback` + + :meth:`_orm.Session.in_transaction` + + + + """ # noqa: E501 + + return self._proxied.is_active + + @property + def autoflush(self) -> Any: + r"""Proxy for the :attr:`_orm.Session.autoflush` attribute + on behalf of the :class:`_asyncio.AsyncSession` class. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class + on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + + """ # noqa: E501 + + return self._proxied.autoflush + + @autoflush.setter + def autoflush(self, attr: Any) -> None: + self._proxied.autoflush = attr + + @property + def no_autoflush(self) -> Any: + r"""Return a context manager that disables autoflush. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class + on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + e.g.:: + + with session.no_autoflush: + + some_object = SomeClass() + session.add(some_object) + # won't autoflush + some_object.related_thing = session.query(SomeRelated).first() + + Operations that proceed within the ``with:`` block + will not be subject to flushes occurring upon query + access. This is useful when initializing a series + of objects which involve existing database queries, + where the uncompleted object should not yet be flushed. + + + + """ # noqa: E501 + + return self._proxied.no_autoflush + + @property + def info(self) -> Any: + r"""A user-modifiable dictionary. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class + on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + The initial value of this dictionary can be populated using the + ``info`` argument to the :class:`.Session` constructor or + :class:`.sessionmaker` constructor or factory methods. The dictionary + here is always local to this :class:`.Session` and can be modified + independently of all other :class:`.Session` objects. + + + + """ # noqa: E501 + + return self._proxied.info + + @classmethod + async def close_all(self): + r"""Close all :class:`_asyncio.AsyncSession` sessions. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + """ # noqa: E501 + + return await AsyncSession.close_all() + + @classmethod + def object_session(cls, instance: Any) -> "Session": + r"""Return the :class:`.Session` to which an object belongs. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This is an alias of :func:`.object_session`. + + + + """ # noqa: E501 + + return AsyncSession.object_session(instance) + + @classmethod + def identity_key( + cls, + class_=None, + ident=None, + *, + instance=None, + row=None, + identity_token=None, + ) -> _IdentityKeyType: + r"""Return an identity key. + + .. container:: class_bases + + Proxied for the :class:`_asyncio.AsyncSession` class on + behalf of the :class:`_asyncio.scoping.async_scoped_session` class. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This is an alias of :func:`.util.identity_key`. + + + + """ # noqa: E501 + + return AsyncSession.identity_key( + class_=class_, + ident=ident, + instance=instance, + row=row, + identity_token=identity_token, + ) + + # END PROXY METHODS async_scoped_session diff --git a/lib/sqlalchemy/ext/asyncio/session.py b/lib/sqlalchemy/ext/asyncio/session.py index c39a8d6e0a..0bd2530b20 100644 --- a/lib/sqlalchemy/ext/asyncio/session.py +++ b/lib/sqlalchemy/ext/asyncio/session.py @@ -4,6 +4,10 @@ # # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php +from __future__ import annotations + +from typing import Any + from . import engine from . import result as _result from .base import ReversibleProxy @@ -312,7 +316,9 @@ class AsyncSession(ReversibleProxy): **kw, ): """Execute a statement and return a streaming - :class:`_asyncio.AsyncResult` object.""" + :class:`_asyncio.AsyncResult` object. + + """ if execution_options: execution_options = util.immutabledict(execution_options).union( @@ -629,6 +635,508 @@ class AsyncSession(ReversibleProxy): # TODO: can this use asynccontextmanager ?? return _AsyncSessionContextManager(self) + # START PROXY METHODS AsyncSession + + # code within this block is **programmatically, + # statically generated** by tools/generate_proxy_methods.py + + def __contains__(self, instance): + r"""Return True if the instance is associated with this session. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + The instance may be pending or persistent within the Session for a + result of True. + + + """ # noqa: E501 + + return self._proxied.__contains__(instance) + + def __iter__(self): + r"""Iterate over all pending or persistent instances within this + Session. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + + """ # noqa: E501 + + return self._proxied.__iter__() + + def add(self, instance: Any, _warn: bool = True) -> None: + r"""Place an object in the ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + Its state will be persisted to the database on the next flush + operation. + + Repeated calls to ``add()`` will be ignored. The opposite of ``add()`` + is ``expunge()``. + + + """ # noqa: E501 + + return self._proxied.add(instance, _warn=_warn) + + def add_all(self, instances): + r"""Add the given collection of instances to this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + """ # noqa: E501 + + return self._proxied.add_all(instances) + + def expire(self, instance, attribute_names=None): + r"""Expire the attributes on an instance. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + Marks the attributes of an instance as out of date. When an expired + attribute is next accessed, a query will be issued to the + :class:`.Session` object's current transactional context in order to + load all expired attributes for the given instance. Note that + a highly isolated transaction will return the same values as were + previously read in that same transaction, regardless of changes + in database state outside of that transaction. + + To expire all objects in the :class:`.Session` simultaneously, + use :meth:`Session.expire_all`. + + The :class:`.Session` object's default behavior is to + expire all state whenever the :meth:`Session.rollback` + or :meth:`Session.commit` methods are called, so that new + state can be loaded for the new transaction. For this reason, + calling :meth:`Session.expire` only makes sense for the specific + case that a non-ORM SQL statement was emitted in the current + transaction. + + :param instance: The instance to be refreshed. + :param attribute_names: optional list of string attribute names + indicating a subset of attributes to be expired. + + .. seealso:: + + :ref:`session_expire` - introductory material + + :meth:`.Session.expire` + + :meth:`.Session.refresh` + + :meth:`_orm.Query.populate_existing` + + + """ # noqa: E501 + + return self._proxied.expire(instance, attribute_names=attribute_names) + + def expire_all(self): + r"""Expires all persistent instances within this Session. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + When any attributes on a persistent instance is next accessed, + a query will be issued using the + :class:`.Session` object's current transactional context in order to + load all expired attributes for the given instance. Note that + a highly isolated transaction will return the same values as were + previously read in that same transaction, regardless of changes + in database state outside of that transaction. + + To expire individual objects and individual attributes + on those objects, use :meth:`Session.expire`. + + The :class:`.Session` object's default behavior is to + expire all state whenever the :meth:`Session.rollback` + or :meth:`Session.commit` methods are called, so that new + state can be loaded for the new transaction. For this reason, + calling :meth:`Session.expire_all` is not usually needed, + assuming the transaction is isolated. + + .. seealso:: + + :ref:`session_expire` - introductory material + + :meth:`.Session.expire` + + :meth:`.Session.refresh` + + :meth:`_orm.Query.populate_existing` + + + """ # noqa: E501 + + return self._proxied.expire_all() + + def expunge(self, instance): + r"""Remove the `instance` from this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This will free all internal references to the instance. Cascading + will be applied according to the *expunge* cascade rule. + + + """ # noqa: E501 + + return self._proxied.expunge(instance) + + def expunge_all(self): + r"""Remove all object instances from this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This is equivalent to calling ``expunge(obj)`` on all objects in this + ``Session``. + + + """ # noqa: E501 + + return self._proxied.expunge_all() + + def is_modified(self, instance, include_collections=True): + r"""Return ``True`` if the given instance has locally + modified attributes. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This method retrieves the history for each instrumented + attribute on the instance and performs a comparison of the current + value to its previously committed value, if any. + + It is in effect a more expensive and accurate + version of checking for the given instance in the + :attr:`.Session.dirty` collection; a full test for + each attribute's net "dirty" status is performed. + + E.g.:: + + return session.is_modified(someobject) + + A few caveats to this method apply: + + * Instances present in the :attr:`.Session.dirty` collection may + report ``False`` when tested with this method. This is because + the object may have received change events via attribute mutation, + thus placing it in :attr:`.Session.dirty`, but ultimately the state + is the same as that loaded from the database, resulting in no net + change here. + * Scalar attributes may not have recorded the previously set + value when a new value was applied, if the attribute was not loaded, + or was expired, at the time the new value was received - in these + cases, the attribute is assumed to have a change, even if there is + ultimately no net change against its database value. SQLAlchemy in + most cases does not need the "old" value when a set event occurs, so + it skips the expense of a SQL call if the old value isn't present, + based on the assumption that an UPDATE of the scalar value is + usually needed, and in those few cases where it isn't, is less + expensive on average than issuing a defensive SELECT. + + The "old" value is fetched unconditionally upon set only if the + attribute container has the ``active_history`` flag set to ``True``. + This flag is set typically for primary key attributes and scalar + object references that are not a simple many-to-one. To set this + flag for any arbitrary mapped column, use the ``active_history`` + argument with :func:`.column_property`. + + :param instance: mapped instance to be tested for pending changes. + :param include_collections: Indicates if multivalued collections + should be included in the operation. Setting this to ``False`` is a + way to detect only local-column based properties (i.e. scalar columns + or many-to-one foreign keys) that would result in an UPDATE for this + instance upon flush. + + + """ # noqa: E501 + + return self._proxied.is_modified( + instance, include_collections=include_collections + ) + + def in_transaction(self): + r"""Return True if this :class:`_orm.Session` has begun a transaction. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + .. versionadded:: 1.4 + + .. seealso:: + + :attr:`_orm.Session.is_active` + + + + """ # noqa: E501 + + return self._proxied.in_transaction() + + def in_nested_transaction(self): + r"""Return True if this :class:`_orm.Session` has begun a nested + transaction, e.g. SAVEPOINT. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + .. versionadded:: 1.4 + + + """ # noqa: E501 + + return self._proxied.in_nested_transaction() + + @property + def dirty(self) -> Any: + r"""The set of all persistent instances considered dirty. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + E.g.:: + + some_mapped_object in session.dirty + + Instances are considered dirty when they were modified but not + deleted. + + Note that this 'dirty' calculation is 'optimistic'; most + attribute-setting or collection modification operations will + mark an instance as 'dirty' and place it in this set, even if + there is no net change to the attribute's value. At flush + time, the value of each attribute is compared to its + previously saved value, and if there's no net change, no SQL + operation will occur (this is a more expensive operation so + it's only done at flush time). + + To check if an instance has actionable net changes to its + attributes, use the :meth:`.Session.is_modified` method. + + + """ # noqa: E501 + + return self._proxied.dirty + + @property + def deleted(self) -> Any: + r"""The set of all instances marked as 'deleted' within this ``Session`` + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + """ # noqa: E501 + + return self._proxied.deleted + + @property + def new(self) -> Any: + r"""The set of all instances marked as 'new' within this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + """ # noqa: E501 + + return self._proxied.new + + @property + def identity_map(self) -> identity.IdentityMap: + r"""Proxy for the :attr:`_orm.Session.identity_map` attribute + on behalf of the :class:`_asyncio.AsyncSession` class. + + """ # noqa: E501 + + return self._proxied.identity_map + + @identity_map.setter + def identity_map(self, attr: identity.IdentityMap) -> None: + self._proxied.identity_map = attr + + @property + def is_active(self) -> Any: + r"""True if this :class:`.Session` not in "partial rollback" state. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + .. versionchanged:: 1.4 The :class:`_orm.Session` no longer begins + a new transaction immediately, so this attribute will be False + when the :class:`_orm.Session` is first instantiated. + + "partial rollback" state typically indicates that the flush process + of the :class:`_orm.Session` has failed, and that the + :meth:`_orm.Session.rollback` method must be emitted in order to + fully roll back the transaction. + + If this :class:`_orm.Session` is not in a transaction at all, the + :class:`_orm.Session` will autobegin when it is first used, so in this + case :attr:`_orm.Session.is_active` will return True. + + Otherwise, if this :class:`_orm.Session` is within a transaction, + and that transaction has not been rolled back internally, the + :attr:`_orm.Session.is_active` will also return True. + + .. seealso:: + + :ref:`faq_session_rollback` + + :meth:`_orm.Session.in_transaction` + + + """ # noqa: E501 + + return self._proxied.is_active + + @property + def autoflush(self) -> bool: + r"""Proxy for the :attr:`_orm.Session.autoflush` attribute + on behalf of the :class:`_asyncio.AsyncSession` class. + + """ # noqa: E501 + + return self._proxied.autoflush + + @autoflush.setter + def autoflush(self, attr: bool) -> None: + self._proxied.autoflush = attr + + @property + def no_autoflush(self) -> Any: + r"""Return a context manager that disables autoflush. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + e.g.:: + + with session.no_autoflush: + + some_object = SomeClass() + session.add(some_object) + # won't autoflush + some_object.related_thing = session.query(SomeRelated).first() + + Operations that proceed within the ``with:`` block + will not be subject to flushes occurring upon query + access. This is useful when initializing a series + of objects which involve existing database queries, + where the uncompleted object should not yet be flushed. + + + """ # noqa: E501 + + return self._proxied.no_autoflush + + @property + def info(self) -> Any: + r"""A user-modifiable dictionary. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_asyncio.AsyncSession` class. + + The initial value of this dictionary can be populated using the + ``info`` argument to the :class:`.Session` constructor or + :class:`.sessionmaker` constructor or factory methods. The dictionary + here is always local to this :class:`.Session` and can be modified + independently of all other :class:`.Session` objects. + + + """ # noqa: E501 + + return self._proxied.info + + @classmethod + def object_session(cls, instance: Any) -> "Session": + r"""Return the :class:`.Session` to which an object belongs. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This is an alias of :func:`.object_session`. + + + """ # noqa: E501 + + return Session.object_session(instance) + + @classmethod + def identity_key( + cls, + class_=None, + ident=None, + *, + instance=None, + row=None, + identity_token=None, + ) -> _IdentityKeyType: + r"""Return an identity key. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_asyncio.AsyncSession` class. + + This is an alias of :func:`.util.identity_key`. + + + """ # noqa: E501 + + return Session.identity_key( + class_=class_, + ident=ident, + instance=instance, + row=row, + identity_token=identity_token, + ) + + # END PROXY METHODS AsyncSession + class _AsyncSessionContextManager: def __init__(self, async_session): diff --git a/lib/sqlalchemy/orm/scoping.py b/lib/sqlalchemy/orm/scoping.py index 9eb80a1072..cc9d5a23b3 100644 --- a/lib/sqlalchemy/orm/scoping.py +++ b/lib/sqlalchemy/orm/scoping.py @@ -11,6 +11,7 @@ from . import exc as orm_exc from .base import class_mapper from .session import Session from .. import exc as sa_exc +from .. import util from ..util import create_proxy_methods from ..util import ScopedRegistry from ..util import ThreadLocalRegistry @@ -225,6 +226,1582 @@ class scoped_session(ScopedSessionMixin): return query() + # START PROXY METHODS scoped_session + + # code within this block is **programmatically, + # statically generated** by tools/generate_proxy_methods.py + + def __contains__(self, instance): + r"""Return True if the instance is associated with this session. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + The instance may be pending or persistent within the Session for a + result of True. + + + """ # noqa: E501 + + return self._proxied.__contains__(instance) + + def __iter__(self): + r"""Iterate over all pending or persistent instances within this + Session. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + + """ # noqa: E501 + + return self._proxied.__iter__() + + def add(self, instance: Any, _warn: bool = True) -> None: + r"""Place an object in the ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + Its state will be persisted to the database on the next flush + operation. + + Repeated calls to ``add()`` will be ignored. The opposite of ``add()`` + is ``expunge()``. + + + """ # noqa: E501 + + return self._proxied.add(instance, _warn=_warn) + + def add_all(self, instances): + r"""Add the given collection of instances to this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + """ # noqa: E501 + + return self._proxied.add_all(instances) + + def begin(self, nested=False, _subtrans=False): + r"""Begin a transaction, or nested transaction, + on this :class:`.Session`, if one is not already begun. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + The :class:`_orm.Session` object features **autobegin** behavior, + so that normally it is not necessary to call the + :meth:`_orm.Session.begin` + method explicitly. However, it may be used in order to control + the scope of when the transactional state is begun. + + When used to begin the outermost transaction, an error is raised + if this :class:`.Session` is already inside of a transaction. + + :param nested: if True, begins a SAVEPOINT transaction and is + equivalent to calling :meth:`~.Session.begin_nested`. For + documentation on SAVEPOINT transactions, please see + :ref:`session_begin_nested`. + + :return: the :class:`.SessionTransaction` object. Note that + :class:`.SessionTransaction` + acts as a Python context manager, allowing :meth:`.Session.begin` + to be used in a "with" block. See :ref:`session_explicit_begin` for + an example. + + .. seealso:: + + :ref:`session_autobegin` + + :ref:`unitofwork_transaction` + + :meth:`.Session.begin_nested` + + + + """ # noqa: E501 + + return self._proxied.begin(nested=nested, _subtrans=_subtrans) + + def begin_nested(self): + r"""Begin a "nested" transaction on this Session, e.g. SAVEPOINT. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + The target database(s) and associated drivers must support SQL + SAVEPOINT for this method to function correctly. + + For documentation on SAVEPOINT + transactions, please see :ref:`session_begin_nested`. + + :return: the :class:`.SessionTransaction` object. Note that + :class:`.SessionTransaction` acts as a context manager, allowing + :meth:`.Session.begin_nested` to be used in a "with" block. + See :ref:`session_begin_nested` for a usage example. + + .. seealso:: + + :ref:`session_begin_nested` + + :ref:`pysqlite_serializable` - special workarounds required + with the SQLite driver in order for SAVEPOINT to work + correctly. + + + """ # noqa: E501 + + return self._proxied.begin_nested() + + def close(self): + r"""Close out the transactional resources and ORM objects used by this + :class:`_orm.Session`. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + This expunges all ORM objects associated with this + :class:`_orm.Session`, ends any transaction in progress and + :term:`releases` any :class:`_engine.Connection` objects which this + :class:`_orm.Session` itself has checked out from associated + :class:`_engine.Engine` objects. The operation then leaves the + :class:`_orm.Session` in a state which it may be used again. + + .. tip:: + + The :meth:`_orm.Session.close` method **does not prevent the + Session from being used again**. The :class:`_orm.Session` itself + does not actually have a distinct "closed" state; it merely means + the :class:`_orm.Session` will release all database connections + and ORM objects. + + .. versionchanged:: 1.4 The :meth:`.Session.close` method does not + immediately create a new :class:`.SessionTransaction` object; + instead, the new :class:`.SessionTransaction` is created only if + the :class:`.Session` is used again for a database operation. + + .. seealso:: + + :ref:`session_closing` - detail on the semantics of + :meth:`_orm.Session.close` + + + """ # noqa: E501 + + return self._proxied.close() + + def commit(self) -> None: + r"""Flush pending changes and commit the current transaction. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + If no transaction is in progress, the method will first + "autobegin" a new transaction and commit. + + The outermost database transaction is committed unconditionally, + automatically releasing any SAVEPOINTs in effect. + + .. seealso:: + + :ref:`session_committing` + + :ref:`unitofwork_transaction` + + + """ # noqa: E501 + + return self._proxied.commit() + + def connection( + self, + bind_arguments: Optional[Dict[str, Any]] = None, + execution_options: Optional["_ExecuteOptions"] = None, + ) -> "Connection": + r"""Return a :class:`_engine.Connection` object corresponding to this + :class:`.Session` object's transactional state. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + Either the :class:`_engine.Connection` corresponding to the current + transaction is returned, or if no transaction is in progress, a new + one is begun and the :class:`_engine.Connection` + returned (note that no + transactional state is established with the DBAPI until the first + SQL statement is emitted). + + Ambiguity in multi-bind or unbound :class:`.Session` objects can be + resolved through any of the optional keyword arguments. This + ultimately makes usage of the :meth:`.get_bind` method for resolution. + + :param bind_arguments: dictionary of bind arguments. May include + "mapper", "bind", "clause", other custom arguments that are passed + to :meth:`.Session.get_bind`. + + :param execution_options: a dictionary of execution options that will + be passed to :meth:`_engine.Connection.execution_options`, **when the + connection is first procured only**. If the connection is already + present within the :class:`.Session`, a warning is emitted and + the arguments are ignored. + + .. seealso:: + + :ref:`session_transaction_isolation` + + + """ # noqa: E501 + + return self._proxied.connection( + bind_arguments=bind_arguments, execution_options=execution_options + ) + + def delete(self, instance): + r"""Mark an instance as deleted. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + The database delete operation occurs upon ``flush()``. + + + """ # noqa: E501 + + return self._proxied.delete(instance) + + def execute( + self, + statement: "Executable", + params: Optional["_ExecuteParams"] = None, + execution_options: "_ExecuteOptions" = util.EMPTY_DICT, + bind_arguments: Optional[Dict[str, Any]] = None, + _parent_execute_state: Optional[Any] = None, + _add_event: Optional[Any] = None, + ): + r"""Execute a SQL expression construct. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + Returns a :class:`_engine.Result` object representing + results of the statement execution. + + E.g.:: + + from sqlalchemy import select + result = session.execute( + select(User).where(User.id == 5) + ) + + The API contract of :meth:`_orm.Session.execute` is similar to that + of :meth:`_engine.Connection.execute`, the :term:`2.0 style` version + of :class:`_engine.Connection`. + + .. versionchanged:: 1.4 the :meth:`_orm.Session.execute` method is + now the primary point of ORM statement execution when using + :term:`2.0 style` ORM usage. + + :param statement: + An executable statement (i.e. an :class:`.Executable` expression + such as :func:`_expression.select`). + + :param params: + Optional dictionary, or list of dictionaries, containing + bound parameter values. If a single dictionary, single-row + execution occurs; if a list of dictionaries, an + "executemany" will be invoked. The keys in each dictionary + must correspond to parameter names present in the statement. + + :param execution_options: optional dictionary of execution options, + which will be associated with the statement execution. This + dictionary can provide a subset of the options that are accepted + by :meth:`_engine.Connection.execution_options`, and may also + provide additional options understood only in an ORM context. + + .. seealso:: + + :ref:`orm_queryguide_execution_options` - ORM-specific execution + options + + :param bind_arguments: dictionary of additional arguments to determine + the bind. May include "mapper", "bind", or other custom arguments. + Contents of this dictionary are passed to the + :meth:`.Session.get_bind` method. + + :return: a :class:`_engine.Result` object. + + + + """ # noqa: E501 + + return self._proxied.execute( + statement, + params=params, + execution_options=execution_options, + bind_arguments=bind_arguments, + _parent_execute_state=_parent_execute_state, + _add_event=_add_event, + ) + + def expire(self, instance, attribute_names=None): + r"""Expire the attributes on an instance. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + Marks the attributes of an instance as out of date. When an expired + attribute is next accessed, a query will be issued to the + :class:`.Session` object's current transactional context in order to + load all expired attributes for the given instance. Note that + a highly isolated transaction will return the same values as were + previously read in that same transaction, regardless of changes + in database state outside of that transaction. + + To expire all objects in the :class:`.Session` simultaneously, + use :meth:`Session.expire_all`. + + The :class:`.Session` object's default behavior is to + expire all state whenever the :meth:`Session.rollback` + or :meth:`Session.commit` methods are called, so that new + state can be loaded for the new transaction. For this reason, + calling :meth:`Session.expire` only makes sense for the specific + case that a non-ORM SQL statement was emitted in the current + transaction. + + :param instance: The instance to be refreshed. + :param attribute_names: optional list of string attribute names + indicating a subset of attributes to be expired. + + .. seealso:: + + :ref:`session_expire` - introductory material + + :meth:`.Session.expire` + + :meth:`.Session.refresh` + + :meth:`_orm.Query.populate_existing` + + + """ # noqa: E501 + + return self._proxied.expire(instance, attribute_names=attribute_names) + + def expire_all(self): + r"""Expires all persistent instances within this Session. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + When any attributes on a persistent instance is next accessed, + a query will be issued using the + :class:`.Session` object's current transactional context in order to + load all expired attributes for the given instance. Note that + a highly isolated transaction will return the same values as were + previously read in that same transaction, regardless of changes + in database state outside of that transaction. + + To expire individual objects and individual attributes + on those objects, use :meth:`Session.expire`. + + The :class:`.Session` object's default behavior is to + expire all state whenever the :meth:`Session.rollback` + or :meth:`Session.commit` methods are called, so that new + state can be loaded for the new transaction. For this reason, + calling :meth:`Session.expire_all` is not usually needed, + assuming the transaction is isolated. + + .. seealso:: + + :ref:`session_expire` - introductory material + + :meth:`.Session.expire` + + :meth:`.Session.refresh` + + :meth:`_orm.Query.populate_existing` + + + """ # noqa: E501 + + return self._proxied.expire_all() + + def expunge(self, instance): + r"""Remove the `instance` from this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + This will free all internal references to the instance. Cascading + will be applied according to the *expunge* cascade rule. + + + """ # noqa: E501 + + return self._proxied.expunge(instance) + + def expunge_all(self): + r"""Remove all object instances from this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + This is equivalent to calling ``expunge(obj)`` on all objects in this + ``Session``. + + + """ # noqa: E501 + + return self._proxied.expunge_all() + + def flush(self, objects=None): + r"""Flush all the object changes to the database. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + Writes out all pending object creations, deletions and modifications + to the database as INSERTs, DELETEs, UPDATEs, etc. Operations are + automatically ordered by the Session's unit of work dependency + solver. + + Database operations will be issued in the current transactional + context and do not affect the state of the transaction, unless an + error occurs, in which case the entire transaction is rolled back. + You may flush() as often as you like within a transaction to move + changes from Python to the database's transaction buffer. + + :param objects: Optional; restricts the flush operation to operate + only on elements that are in the given collection. + + This feature is for an extremely narrow set of use cases where + particular objects may need to be operated upon before the + full flush() occurs. It is not intended for general use. + + + """ # noqa: E501 + + return self._proxied.flush(objects=objects) + + def get( + self, + entity, + ident, + options=None, + populate_existing=False, + with_for_update=None, + identity_token=None, + execution_options=None, + ): + r"""Return an instance based on the given primary key identifier, + or ``None`` if not found. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + E.g.:: + + my_user = session.get(User, 5) + + some_object = session.get(VersionedFoo, (5, 10)) + + some_object = session.get( + VersionedFoo, + {"id": 5, "version_id": 10} + ) + + .. versionadded:: 1.4 Added :meth:`_orm.Session.get`, which is moved + from the now legacy :meth:`_orm.Query.get` method. + + :meth:`_orm.Session.get` is special in that it provides direct + access to the identity map of the :class:`.Session`. + If the given primary key identifier is present + in the local identity map, the object is returned + directly from this collection and no SQL is emitted, + unless the object has been marked fully expired. + If not present, + a SELECT is performed in order to locate the object. + + :meth:`_orm.Session.get` also will perform a check if + the object is present in the identity map and + marked as expired - a SELECT + is emitted to refresh the object as well as to + ensure that the row is still present. + If not, :class:`~sqlalchemy.orm.exc.ObjectDeletedError` is raised. + + :param entity: a mapped class or :class:`.Mapper` indicating the + type of entity to be loaded. + + :param ident: A scalar, tuple, or dictionary representing the + primary key. For a composite (e.g. multiple column) primary key, + a tuple or dictionary should be passed. + + For a single-column primary key, the scalar calling form is typically + the most expedient. If the primary key of a row is the value "5", + the call looks like:: + + my_object = session.get(SomeClass, 5) + + The tuple form contains primary key values typically in + the order in which they correspond to the mapped + :class:`_schema.Table` + object's primary key columns, or if the + :paramref:`_orm.Mapper.primary_key` configuration parameter were + used, in + the order used for that parameter. For example, if the primary key + of a row is represented by the integer + digits "5, 10" the call would look like:: + + my_object = session.get(SomeClass, (5, 10)) + + The dictionary form should include as keys the mapped attribute names + corresponding to each element of the primary key. If the mapped class + has the attributes ``id``, ``version_id`` as the attributes which + store the object's primary key value, the call would look like:: + + my_object = session.get(SomeClass, {"id": 5, "version_id": 10}) + + :param options: optional sequence of loader options which will be + applied to the query, if one is emitted. + + :param populate_existing: causes the method to unconditionally emit + a SQL query and refresh the object with the newly loaded data, + regardless of whether or not the object is already present. + + :param with_for_update: optional boolean ``True`` indicating FOR UPDATE + should be used, or may be a dictionary containing flags to + indicate a more specific set of FOR UPDATE flags for the SELECT; + flags should match the parameters of + :meth:`_query.Query.with_for_update`. + Supersedes the :paramref:`.Session.refresh.lockmode` parameter. + + :param execution_options: optional dictionary of execution options, + which will be associated with the query execution if one is emitted. + This dictionary can provide a subset of the options that are + accepted by :meth:`_engine.Connection.execution_options`, and may + also provide additional options understood only in an ORM context. + + .. versionadded:: 1.4.29 + + .. seealso:: + + :ref:`orm_queryguide_execution_options` - ORM-specific execution + options + + :return: The object instance, or ``None``. + + + """ # noqa: E501 + + return self._proxied.get( + entity, + ident, + options=options, + populate_existing=populate_existing, + with_for_update=with_for_update, + identity_token=identity_token, + execution_options=execution_options, + ) + + def get_bind( + self, + mapper=None, + clause=None, + bind=None, + _sa_skip_events=None, + _sa_skip_for_implicit_returning=False, + ): + r"""Return a "bind" to which this :class:`.Session` is bound. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + The "bind" is usually an instance of :class:`_engine.Engine`, + except in the case where the :class:`.Session` has been + explicitly bound directly to a :class:`_engine.Connection`. + + For a multiply-bound or unbound :class:`.Session`, the + ``mapper`` or ``clause`` arguments are used to determine the + appropriate bind to return. + + Note that the "mapper" argument is usually present + when :meth:`.Session.get_bind` is called via an ORM + operation such as a :meth:`.Session.query`, each + individual INSERT/UPDATE/DELETE operation within a + :meth:`.Session.flush`, call, etc. + + The order of resolution is: + + 1. if mapper given and :paramref:`.Session.binds` is present, + locate a bind based first on the mapper in use, then + on the mapped class in use, then on any base classes that are + present in the ``__mro__`` of the mapped class, from more specific + superclasses to more general. + 2. if clause given and ``Session.binds`` is present, + locate a bind based on :class:`_schema.Table` objects + found in the given clause present in ``Session.binds``. + 3. if ``Session.binds`` is present, return that. + 4. if clause given, attempt to return a bind + linked to the :class:`_schema.MetaData` ultimately + associated with the clause. + 5. if mapper given, attempt to return a bind + linked to the :class:`_schema.MetaData` ultimately + associated with the :class:`_schema.Table` or other + selectable to which the mapper is mapped. + 6. No bind can be found, :exc:`~sqlalchemy.exc.UnboundExecutionError` + is raised. + + Note that the :meth:`.Session.get_bind` method can be overridden on + a user-defined subclass of :class:`.Session` to provide any kind + of bind resolution scheme. See the example at + :ref:`session_custom_partitioning`. + + :param mapper: + Optional mapped class or corresponding :class:`_orm.Mapper` instance. + The bind can be derived from a :class:`_orm.Mapper` first by + consulting the "binds" map associated with this :class:`.Session`, + and secondly by consulting the :class:`_schema.MetaData` associated + with the :class:`_schema.Table` to which the :class:`_orm.Mapper` is + mapped for a bind. + + :param clause: + A :class:`_expression.ClauseElement` (i.e. + :func:`_expression.select`, + :func:`_expression.text`, + etc.). If the ``mapper`` argument is not present or could not + produce a bind, the given expression construct will be searched + for a bound element, typically a :class:`_schema.Table` + associated with + bound :class:`_schema.MetaData`. + + .. seealso:: + + :ref:`session_partitioning` + + :paramref:`.Session.binds` + + :meth:`.Session.bind_mapper` + + :meth:`.Session.bind_table` + + + """ # noqa: E501 + + return self._proxied.get_bind( + mapper=mapper, + clause=clause, + bind=bind, + _sa_skip_events=_sa_skip_events, + _sa_skip_for_implicit_returning=_sa_skip_for_implicit_returning, + ) + + def is_modified(self, instance, include_collections=True): + r"""Return ``True`` if the given instance has locally + modified attributes. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + This method retrieves the history for each instrumented + attribute on the instance and performs a comparison of the current + value to its previously committed value, if any. + + It is in effect a more expensive and accurate + version of checking for the given instance in the + :attr:`.Session.dirty` collection; a full test for + each attribute's net "dirty" status is performed. + + E.g.:: + + return session.is_modified(someobject) + + A few caveats to this method apply: + + * Instances present in the :attr:`.Session.dirty` collection may + report ``False`` when tested with this method. This is because + the object may have received change events via attribute mutation, + thus placing it in :attr:`.Session.dirty`, but ultimately the state + is the same as that loaded from the database, resulting in no net + change here. + * Scalar attributes may not have recorded the previously set + value when a new value was applied, if the attribute was not loaded, + or was expired, at the time the new value was received - in these + cases, the attribute is assumed to have a change, even if there is + ultimately no net change against its database value. SQLAlchemy in + most cases does not need the "old" value when a set event occurs, so + it skips the expense of a SQL call if the old value isn't present, + based on the assumption that an UPDATE of the scalar value is + usually needed, and in those few cases where it isn't, is less + expensive on average than issuing a defensive SELECT. + + The "old" value is fetched unconditionally upon set only if the + attribute container has the ``active_history`` flag set to ``True``. + This flag is set typically for primary key attributes and scalar + object references that are not a simple many-to-one. To set this + flag for any arbitrary mapped column, use the ``active_history`` + argument with :func:`.column_property`. + + :param instance: mapped instance to be tested for pending changes. + :param include_collections: Indicates if multivalued collections + should be included in the operation. Setting this to ``False`` is a + way to detect only local-column based properties (i.e. scalar columns + or many-to-one foreign keys) that would result in an UPDATE for this + instance upon flush. + + + """ # noqa: E501 + + return self._proxied.is_modified( + instance, include_collections=include_collections + ) + + def bulk_save_objects( + self, + objects, + return_defaults=False, + update_changed_only=True, + preserve_order=True, + ): + r"""Perform a bulk save of the given list of objects. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + The bulk save feature allows mapped objects to be used as the + source of simple INSERT and UPDATE operations which can be more easily + grouped together into higher performing "executemany" + operations; the extraction of data from the objects is also performed + using a lower-latency process that ignores whether or not attributes + have actually been modified in the case of UPDATEs, and also ignores + SQL expressions. + + The objects as given are not added to the session and no additional + state is established on them. If the + :paramref:`_orm.Session.bulk_save_objects.return_defaults` flag is set, + then server-generated primary key values will be assigned to the + returned objects, but **not server side defaults**; this is a + limitation in the implementation. If stateful objects are desired, + please use the standard :meth:`_orm.Session.add_all` approach or + as an alternative newer mass-insert features such as + :ref:`orm_dml_returning_objects`. + + .. warning:: + + The bulk save feature allows for a lower-latency INSERT/UPDATE + of rows at the expense of most other unit-of-work features. + Features such as object management, relationship handling, + and SQL clause support are **silently omitted** in favor of raw + INSERT/UPDATES of records. + + Please note that newer versions of SQLAlchemy are **greatly + improving the efficiency** of the standard flush process. It is + **strongly recommended** to not use the bulk methods as they + represent a forking of SQLAlchemy's functionality and are slowly + being moved into legacy status. New features such as + :ref:`orm_dml_returning_objects` are both more efficient than + the "bulk" methods and provide more predictable functionality. + + **Please read the list of caveats at** + :ref:`bulk_operations_caveats` **before using this method, and + fully test and confirm the functionality of all code developed + using these systems.** + + :param objects: a sequence of mapped object instances. The mapped + objects are persisted as is, and are **not** associated with the + :class:`.Session` afterwards. + + For each object, whether the object is sent as an INSERT or an + UPDATE is dependent on the same rules used by the :class:`.Session` + in traditional operation; if the object has the + :attr:`.InstanceState.key` + attribute set, then the object is assumed to be "detached" and + will result in an UPDATE. Otherwise, an INSERT is used. + + In the case of an UPDATE, statements are grouped based on which + attributes have changed, and are thus to be the subject of each + SET clause. If ``update_changed_only`` is False, then all + attributes present within each object are applied to the UPDATE + statement, which may help in allowing the statements to be grouped + together into a larger executemany(), and will also reduce the + overhead of checking history on attributes. + + :param return_defaults: when True, rows that are missing values which + generate defaults, namely integer primary key defaults and sequences, + will be inserted **one at a time**, so that the primary key value + is available. In particular this will allow joined-inheritance + and other multi-table mappings to insert correctly without the need + to provide primary key values ahead of time; however, + :paramref:`.Session.bulk_save_objects.return_defaults` **greatly + reduces the performance gains** of the method overall. It is strongly + advised to please use the standard :meth:`_orm.Session.add_all` + approach. + + :param update_changed_only: when True, UPDATE statements are rendered + based on those attributes in each state that have logged changes. + When False, all attributes present are rendered into the SET clause + with the exception of primary key attributes. + + :param preserve_order: when True, the order of inserts and updates + matches exactly the order in which the objects are given. When + False, common types of objects are grouped into inserts + and updates, to allow for more batching opportunities. + + .. versionadded:: 1.3 + + .. seealso:: + + :ref:`bulk_operations` + + :meth:`.Session.bulk_insert_mappings` + + :meth:`.Session.bulk_update_mappings` + + + """ # noqa: E501 + + return self._proxied.bulk_save_objects( + objects, + return_defaults=return_defaults, + update_changed_only=update_changed_only, + preserve_order=preserve_order, + ) + + def bulk_insert_mappings( + self, mapper, mappings, return_defaults=False, render_nulls=False + ): + r"""Perform a bulk insert of the given list of mapping dictionaries. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + The bulk insert feature allows plain Python dictionaries to be used as + the source of simple INSERT operations which can be more easily + grouped together into higher performing "executemany" + operations. Using dictionaries, there is no "history" or session + state management features in use, reducing latency when inserting + large numbers of simple rows. + + The values within the dictionaries as given are typically passed + without modification into Core :meth:`_expression.Insert` constructs, + after + organizing the values within them across the tables to which + the given mapper is mapped. + + .. versionadded:: 1.0.0 + + .. warning:: + + The bulk insert feature allows for a lower-latency INSERT + of rows at the expense of most other unit-of-work features. + Features such as object management, relationship handling, + and SQL clause support are **silently omitted** in favor of raw + INSERT of records. + + Please note that newer versions of SQLAlchemy are **greatly + improving the efficiency** of the standard flush process. It is + **strongly recommended** to not use the bulk methods as they + represent a forking of SQLAlchemy's functionality and are slowly + being moved into legacy status. New features such as + :ref:`orm_dml_returning_objects` are both more efficient than + the "bulk" methods and provide more predictable functionality. + + **Please read the list of caveats at** + :ref:`bulk_operations_caveats` **before using this method, and + fully test and confirm the functionality of all code developed + using these systems.** + + :param mapper: a mapped class, or the actual :class:`_orm.Mapper` + object, + representing the single kind of object represented within the mapping + list. + + :param mappings: a sequence of dictionaries, each one containing the + state of the mapped row to be inserted, in terms of the attribute + names on the mapped class. If the mapping refers to multiple tables, + such as a joined-inheritance mapping, each dictionary must contain all + keys to be populated into all tables. + + :param return_defaults: when True, rows that are missing values which + generate defaults, namely integer primary key defaults and sequences, + will be inserted **one at a time**, so that the primary key value + is available. In particular this will allow joined-inheritance + and other multi-table mappings to insert correctly without the need + to provide primary + key values ahead of time; however, + :paramref:`.Session.bulk_insert_mappings.return_defaults` + **greatly reduces the performance gains** of the method overall. + If the rows + to be inserted only refer to a single table, then there is no + reason this flag should be set as the returned default information + is not used. + + :param render_nulls: When True, a value of ``None`` will result + in a NULL value being included in the INSERT statement, rather + than the column being omitted from the INSERT. This allows all + the rows being INSERTed to have the identical set of columns which + allows the full set of rows to be batched to the DBAPI. Normally, + each column-set that contains a different combination of NULL values + than the previous row must omit a different series of columns from + the rendered INSERT statement, which means it must be emitted as a + separate statement. By passing this flag, the full set of rows + are guaranteed to be batchable into one batch; the cost however is + that server-side defaults which are invoked by an omitted column will + be skipped, so care must be taken to ensure that these are not + necessary. + + .. warning:: + + When this flag is set, **server side default SQL values will + not be invoked** for those columns that are inserted as NULL; + the NULL value will be sent explicitly. Care must be taken + to ensure that no server-side default functions need to be + invoked for the operation as a whole. + + .. versionadded:: 1.1 + + .. seealso:: + + :ref:`bulk_operations` + + :meth:`.Session.bulk_save_objects` + + :meth:`.Session.bulk_update_mappings` + + + """ # noqa: E501 + + return self._proxied.bulk_insert_mappings( + mapper, + mappings, + return_defaults=return_defaults, + render_nulls=render_nulls, + ) + + def bulk_update_mappings(self, mapper, mappings): + r"""Perform a bulk update of the given list of mapping dictionaries. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + The bulk update feature allows plain Python dictionaries to be used as + the source of simple UPDATE operations which can be more easily + grouped together into higher performing "executemany" + operations. Using dictionaries, there is no "history" or session + state management features in use, reducing latency when updating + large numbers of simple rows. + + .. versionadded:: 1.0.0 + + .. warning:: + + The bulk update feature allows for a lower-latency UPDATE + of rows at the expense of most other unit-of-work features. + Features such as object management, relationship handling, + and SQL clause support are **silently omitted** in favor of raw + UPDATES of records. + + Please note that newer versions of SQLAlchemy are **greatly + improving the efficiency** of the standard flush process. It is + **strongly recommended** to not use the bulk methods as they + represent a forking of SQLAlchemy's functionality and are slowly + being moved into legacy status. New features such as + :ref:`orm_dml_returning_objects` are both more efficient than + the "bulk" methods and provide more predictable functionality. + + **Please read the list of caveats at** + :ref:`bulk_operations_caveats` **before using this method, and + fully test and confirm the functionality of all code developed + using these systems.** + + :param mapper: a mapped class, or the actual :class:`_orm.Mapper` + object, + representing the single kind of object represented within the mapping + list. + + :param mappings: a sequence of dictionaries, each one containing the + state of the mapped row to be updated, in terms of the attribute names + on the mapped class. If the mapping refers to multiple tables, such + as a joined-inheritance mapping, each dictionary may contain keys + corresponding to all tables. All those keys which are present and + are not part of the primary key are applied to the SET clause of the + UPDATE statement; the primary key values, which are required, are + applied to the WHERE clause. + + + .. seealso:: + + :ref:`bulk_operations` + + :meth:`.Session.bulk_insert_mappings` + + :meth:`.Session.bulk_save_objects` + + + """ # noqa: E501 + + return self._proxied.bulk_update_mappings(mapper, mappings) + + def merge(self, instance, load=True, options=None): + r"""Copy the state of a given instance into a corresponding instance + within this :class:`.Session`. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + :meth:`.Session.merge` examines the primary key attributes of the + source instance, and attempts to reconcile it with an instance of the + same primary key in the session. If not found locally, it attempts + to load the object from the database based on primary key, and if + none can be located, creates a new instance. The state of each + attribute on the source instance is then copied to the target + instance. The resulting target instance is then returned by the + method; the original source instance is left unmodified, and + un-associated with the :class:`.Session` if not already. + + This operation cascades to associated instances if the association is + mapped with ``cascade="merge"``. + + See :ref:`unitofwork_merging` for a detailed discussion of merging. + + .. versionchanged:: 1.1 - :meth:`.Session.merge` will now reconcile + pending objects with overlapping primary keys in the same way + as persistent. See :ref:`change_3601` for discussion. + + :param instance: Instance to be merged. + :param load: Boolean, when False, :meth:`.merge` switches into + a "high performance" mode which causes it to forego emitting history + events as well as all database access. This flag is used for + cases such as transferring graphs of objects into a :class:`.Session` + from a second level cache, or to transfer just-loaded objects + into the :class:`.Session` owned by a worker thread or process + without re-querying the database. + + The ``load=False`` use case adds the caveat that the given + object has to be in a "clean" state, that is, has no pending changes + to be flushed - even if the incoming object is detached from any + :class:`.Session`. This is so that when + the merge operation populates local attributes and + cascades to related objects and + collections, the values can be "stamped" onto the + target object as is, without generating any history or attribute + events, and without the need to reconcile the incoming data with + any existing related objects or collections that might not + be loaded. The resulting objects from ``load=False`` are always + produced as "clean", so it is only appropriate that the given objects + should be "clean" as well, else this suggests a mis-use of the + method. + :param options: optional sequence of loader options which will be + applied to the :meth:`_orm.Session.get` method when the merge + operation loads the existing version of the object from the database. + + .. versionadded:: 1.4.24 + + + .. seealso:: + + :func:`.make_transient_to_detached` - provides for an alternative + means of "merging" a single object into the :class:`.Session` + + + """ # noqa: E501 + + return self._proxied.merge(instance, load=load, options=options) + + def query(self, *entities: _ColumnsClauseArgument, **kwargs: Any) -> Query: + r"""Return a new :class:`_query.Query` object corresponding to this + :class:`_orm.Session`. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + Note that the :class:`_query.Query` object is legacy as of + SQLAlchemy 2.0; the :func:`_sql.select` construct is now used + to construct ORM queries. + + .. seealso:: + + :ref:`unified_tutorial` + + :ref:`queryguide_toplevel` + + :ref:`query_api_toplevel` - legacy API doc + + + """ # noqa: E501 + + return self._proxied.query(*entities, **kwargs) + + def refresh(self, instance, attribute_names=None, with_for_update=None): + r"""Expire and refresh attributes on the given instance. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + The selected attributes will first be expired as they would when using + :meth:`_orm.Session.expire`; then a SELECT statement will be issued to + the database to refresh column-oriented attributes with the current + value available in the current transaction. + + :func:`_orm.relationship` oriented attributes will also be immediately + loaded if they were already eagerly loaded on the object, using the + same eager loading strategy that they were loaded with originally. + Unloaded relationship attributes will remain unloaded, as will + relationship attributes that were originally lazy loaded. + + .. versionadded:: 1.4 - the :meth:`_orm.Session.refresh` method + can also refresh eagerly loaded attributes. + + .. tip:: + + While the :meth:`_orm.Session.refresh` method is capable of + refreshing both column and relationship oriented attributes, its + primary focus is on refreshing of local column-oriented attributes + on a single instance. For more open ended "refresh" functionality, + including the ability to refresh the attributes on many objects at + once while having explicit control over relationship loader + strategies, use the + :ref:`populate existing ` feature + instead. + + Note that a highly isolated transaction will return the same values as + were previously read in that same transaction, regardless of changes + in database state outside of that transaction. Refreshing + attributes usually only makes sense at the start of a transaction + where database rows have not yet been accessed. + + :param attribute_names: optional. An iterable collection of + string attribute names indicating a subset of attributes to + be refreshed. + + :param with_for_update: optional boolean ``True`` indicating FOR UPDATE + should be used, or may be a dictionary containing flags to + indicate a more specific set of FOR UPDATE flags for the SELECT; + flags should match the parameters of + :meth:`_query.Query.with_for_update`. + Supersedes the :paramref:`.Session.refresh.lockmode` parameter. + + .. seealso:: + + :ref:`session_expire` - introductory material + + :meth:`.Session.expire` + + :meth:`.Session.expire_all` + + :ref:`orm_queryguide_populate_existing` - allows any ORM query + to refresh objects as they would be loaded normally. + + + """ # noqa: E501 + + return self._proxied.refresh( + instance, + attribute_names=attribute_names, + with_for_update=with_for_update, + ) + + def rollback(self): + r"""Rollback the current transaction in progress. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + If no transaction is in progress, this method is a pass-through. + + The method always rolls back + the topmost database transaction, discarding any nested + transactions that may be in progress. + + .. seealso:: + + :ref:`session_rollback` + + :ref:`unitofwork_transaction` + + + """ # noqa: E501 + + return self._proxied.rollback() + + def scalar( + self, + statement, + params=None, + execution_options=util.EMPTY_DICT, + bind_arguments=None, + **kw, + ): + r"""Execute a statement and return a scalar result. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + Usage and parameters are the same as that of + :meth:`_orm.Session.execute`; the return result is a scalar Python + value. + + + """ # noqa: E501 + + return self._proxied.scalar( + statement, + params=params, + execution_options=execution_options, + bind_arguments=bind_arguments, + **kw, + ) + + def scalars( + self, + statement, + params=None, + execution_options=util.EMPTY_DICT, + bind_arguments=None, + **kw, + ): + r"""Execute a statement and return the results as scalars. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + Usage and parameters are the same as that of + :meth:`_orm.Session.execute`; the return result is a + :class:`_result.ScalarResult` filtering object which + will return single elements rather than :class:`_row.Row` objects. + + :return: a :class:`_result.ScalarResult` object + + .. versionadded:: 1.4.24 + + + """ # noqa: E501 + + return self._proxied.scalars( + statement, + params=params, + execution_options=execution_options, + bind_arguments=bind_arguments, + **kw, + ) + + @property + def bind(self) -> Optional[Union[Engine, Connection]]: + r"""Proxy for the :attr:`_orm.Session.bind` attribute + on behalf of the :class:`_orm.scoping.scoped_session` class. + + """ # noqa: E501 + + return self._proxied.bind + + @bind.setter + def bind(self, attr: Optional[Union[Engine, Connection]]) -> None: + self._proxied.bind = attr + + @property + def dirty(self) -> Any: + r"""The set of all persistent instances considered dirty. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_orm.scoping.scoped_session` class. + + E.g.:: + + some_mapped_object in session.dirty + + Instances are considered dirty when they were modified but not + deleted. + + Note that this 'dirty' calculation is 'optimistic'; most + attribute-setting or collection modification operations will + mark an instance as 'dirty' and place it in this set, even if + there is no net change to the attribute's value. At flush + time, the value of each attribute is compared to its + previously saved value, and if there's no net change, no SQL + operation will occur (this is a more expensive operation so + it's only done at flush time). + + To check if an instance has actionable net changes to its + attributes, use the :meth:`.Session.is_modified` method. + + + """ # noqa: E501 + + return self._proxied.dirty + + @property + def deleted(self) -> Any: + r"""The set of all instances marked as 'deleted' within this ``Session`` + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_orm.scoping.scoped_session` class. + + """ # noqa: E501 + + return self._proxied.deleted + + @property + def new(self) -> Any: + r"""The set of all instances marked as 'new' within this ``Session``. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_orm.scoping.scoped_session` class. + + """ # noqa: E501 + + return self._proxied.new + + @property + def identity_map(self) -> identity.IdentityMap: + r"""Proxy for the :attr:`_orm.Session.identity_map` attribute + on behalf of the :class:`_orm.scoping.scoped_session` class. + + """ # noqa: E501 + + return self._proxied.identity_map + + @identity_map.setter + def identity_map(self, attr: identity.IdentityMap) -> None: + self._proxied.identity_map = attr + + @property + def is_active(self) -> Any: + r"""True if this :class:`.Session` not in "partial rollback" state. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_orm.scoping.scoped_session` class. + + .. versionchanged:: 1.4 The :class:`_orm.Session` no longer begins + a new transaction immediately, so this attribute will be False + when the :class:`_orm.Session` is first instantiated. + + "partial rollback" state typically indicates that the flush process + of the :class:`_orm.Session` has failed, and that the + :meth:`_orm.Session.rollback` method must be emitted in order to + fully roll back the transaction. + + If this :class:`_orm.Session` is not in a transaction at all, the + :class:`_orm.Session` will autobegin when it is first used, so in this + case :attr:`_orm.Session.is_active` will return True. + + Otherwise, if this :class:`_orm.Session` is within a transaction, + and that transaction has not been rolled back internally, the + :attr:`_orm.Session.is_active` will also return True. + + .. seealso:: + + :ref:`faq_session_rollback` + + :meth:`_orm.Session.in_transaction` + + + """ # noqa: E501 + + return self._proxied.is_active + + @property + def autoflush(self) -> bool: + r"""Proxy for the :attr:`_orm.Session.autoflush` attribute + on behalf of the :class:`_orm.scoping.scoped_session` class. + + """ # noqa: E501 + + return self._proxied.autoflush + + @autoflush.setter + def autoflush(self, attr: bool) -> None: + self._proxied.autoflush = attr + + @property + def no_autoflush(self) -> Any: + r"""Return a context manager that disables autoflush. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_orm.scoping.scoped_session` class. + + e.g.:: + + with session.no_autoflush: + + some_object = SomeClass() + session.add(some_object) + # won't autoflush + some_object.related_thing = session.query(SomeRelated).first() + + Operations that proceed within the ``with:`` block + will not be subject to flushes occurring upon query + access. This is useful when initializing a series + of objects which involve existing database queries, + where the uncompleted object should not yet be flushed. + + + """ # noqa: E501 + + return self._proxied.no_autoflush + + @property + def info(self) -> Any: + r"""A user-modifiable dictionary. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class + on behalf of the :class:`_orm.scoping.scoped_session` class. + + The initial value of this dictionary can be populated using the + ``info`` argument to the :class:`.Session` constructor or + :class:`.sessionmaker` constructor or factory methods. The dictionary + here is always local to this :class:`.Session` and can be modified + independently of all other :class:`.Session` objects. + + + """ # noqa: E501 + + return self._proxied.info + + @property + def autocommit(self) -> Any: + r"""Proxy for the :attr:`_orm.Session.autocommit` attribute + on behalf of the :class:`_orm.scoping.scoped_session` class. + + """ # noqa: E501 + + return self._proxied.autocommit + + @autocommit.setter + def autocommit(self, attr: Any) -> None: + self._proxied.autocommit = attr + + @classmethod + def close_all(cls) -> None: + r"""Close *all* sessions in memory. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + .. deprecated:: 1.3 The :meth:`.Session.close_all` method is deprecated and will be removed in a future release. Please refer to :func:`.session.close_all_sessions`. + + """ # noqa: E501 + + return Session.close_all() + + @classmethod + def object_session(cls, instance: Any) -> "Session": + r"""Return the :class:`.Session` to which an object belongs. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + This is an alias of :func:`.object_session`. + + + """ # noqa: E501 + + return Session.object_session(instance) + + @classmethod + def identity_key( + cls, + class_=None, + ident=None, + *, + instance=None, + row=None, + identity_token=None, + ) -> _IdentityKeyType: + r"""Return an identity key. + + .. container:: class_bases + + Proxied for the :class:`_orm.Session` class on + behalf of the :class:`_orm.scoping.scoped_session` class. + + This is an alias of :func:`.util.identity_key`. + + + """ # noqa: E501 + + return Session.identity_key( + class_=class_, + ident=ident, + instance=instance, + row=row, + identity_token=identity_token, + ) + + # END PROXY METHODS scoped_session + ScopedSession = scoped_session """Old name for backwards compatibility.""" diff --git a/lib/sqlalchemy/orm/session.py b/lib/sqlalchemy/orm/session.py index 6279c17fbc..77a97936b2 100644 --- a/lib/sqlalchemy/orm/session.py +++ b/lib/sqlalchemy/orm/session.py @@ -56,7 +56,6 @@ from ..sql import coercions from ..sql import dml from ..sql import roles from ..sql import visitors -from ..sql._typing import _ColumnsClauseArgument from ..sql.base import CompileState from ..sql.selectable import LABEL_STYLE_TABLENAME_PLUS_COL from ..util.typing import Literal @@ -64,6 +63,7 @@ from ..util.typing import Literal if typing.TYPE_CHECKING: from .mapper import Mapper from ..engine import Row + from ..sql._typing import _ColumnsClauseArgument from ..sql._typing import _ExecuteOptions from ..sql._typing import _ExecuteParams from ..sql.base import Executable @@ -2043,9 +2043,7 @@ class Session(_SessionClassMethods): % (", ".join(context),), ) - def query( - self, *entities: "_ColumnsClauseArgument", **kwargs: Any - ) -> "Query": + def query(self, *entities: _ColumnsClauseArgument, **kwargs: Any) -> Query: """Return a new :class:`_query.Query` object corresponding to this :class:`_orm.Session`. diff --git a/lib/sqlalchemy/testing/plugin/plugin_base.py b/lib/sqlalchemy/testing/plugin/plugin_base.py index 52e42bb974..b908585128 100644 --- a/lib/sqlalchemy/testing/plugin/plugin_base.py +++ b/lib/sqlalchemy/testing/plugin/plugin_base.py @@ -5,14 +5,8 @@ # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php -"""Testing extensions. - -this module is designed to work as a testing-framework-agnostic library, -created so that multiple test frameworks can be supported at once -(mostly so that we can migrate to new ones). The current target -is pytest. +from __future__ import annotations -""" import abc import configparser import logging @@ -23,6 +17,15 @@ from typing import Any from sqlalchemy.testing import asyncio +"""Testing extensions. + +this module is designed to work as a testing-framework-agnostic library, +created so that multiple test frameworks can be supported at once +(mostly so that we can migrate to new ones). The current target +is pytest. + +""" + # flag which indicates we are in the SQLAlchemy testing suite, # and not that of Alembic or a third party dialect. bootstrapped_as_sqlalchemy = False diff --git a/lib/sqlalchemy/testing/plugin/pytestplugin.py b/lib/sqlalchemy/testing/plugin/pytestplugin.py index 6efeac5049..ab93e60e25 100644 --- a/lib/sqlalchemy/testing/plugin/pytestplugin.py +++ b/lib/sqlalchemy/testing/plugin/pytestplugin.py @@ -1,9 +1,4 @@ -try: - # installed by bootstrap.py - import sqla_plugin_base as plugin_base -except ImportError: - # assume we're a package, use traditional import - from . import plugin_base +from __future__ import annotations import argparse import collections @@ -17,6 +12,13 @@ import uuid import pytest +try: + # installed by bootstrap.py + import sqla_plugin_base as plugin_base +except ImportError: + # assume we're a package, use traditional import + from . import plugin_base + def pytest_addoption(parser): group = parser.getgroup("sqlalchemy") @@ -565,6 +567,10 @@ def _pytest_fn_decorator(target): from sqlalchemy.util.compat import inspect_getfullargspec def _exec_code_in_env(code, env, fn_name): + # note this is affected by "from __future__ import annotations" at + # the top; exec'ed code will use non-evaluated annotations + # which allows us to be more flexible with code rendering + # in format_argpsec_plus() exec(code, env) return env[fn_name] diff --git a/lib/sqlalchemy/util/compat.py b/lib/sqlalchemy/util/compat.py index d30236dd9d..aeaefa40e3 100644 --- a/lib/sqlalchemy/util/compat.py +++ b/lib/sqlalchemy/util/compat.py @@ -139,17 +139,17 @@ def _formatannotation(annotation, base_module=None): """vendored from python 3.7""" if isinstance(annotation, str): - return f'"{annotation}"' + return annotation if getattr(annotation, "__module__", None) == "typing": - return f'"{repr(annotation).replace("typing.", "").replace("~", "")}"' + return repr(annotation).replace("typing.", "").replace("~", "") if isinstance(annotation, type): if annotation.__module__ in ("builtins", base_module): return repr(annotation.__qualname__) return annotation.__module__ + "." + annotation.__qualname__ elif isinstance(annotation, typing.TypeVar): - return f'"{repr(annotation).replace("~", "")}"' - return f'"{repr(annotation).replace("~", "")}"' + return repr(annotation).replace("~", "") + return repr(annotation).replace("~", "") def inspect_formatargspec( diff --git a/lib/sqlalchemy/util/langhelpers.py b/lib/sqlalchemy/util/langhelpers.py index 8f0ec700f9..3e89c72bbb 100644 --- a/lib/sqlalchemy/util/langhelpers.py +++ b/lib/sqlalchemy/util/langhelpers.py @@ -678,111 +678,17 @@ def create_proxy_methods( methods=(), attributes=(), ): - """A class decorator that will copy attributes to a proxy class. + """A class decorator indicating attributes should refer to a proxy + class. - The class to be instrumented must define a single accessor "_proxied". + This decorator is now a "marker" that does nothing at runtime. Instead, + it is consumed by the tools/generate_proxy_methods.py script to + statically generate proxy methods and attributes that are fully + recognized by typing tools such as mypy. """ def decorate(cls): - def instrument(name, clslevel=False): - fn = cast(types.FunctionType, getattr(target_cls, name)) - spec = compat.inspect_getfullargspec(fn) - env = {"__name__": fn.__module__} - - spec = _update_argspec_defaults_into_env(spec, env) - caller_argspec = format_argspec_plus(spec, grouped=False) - - metadata = { - "name": fn.__name__, - "apply_pos_proxied": caller_argspec["apply_pos_proxied"], - "apply_kw_proxied": caller_argspec["apply_kw_proxied"], - "grouped_args": caller_argspec["grouped_args"], - "self_arg": caller_argspec["self_arg"], - } - - if clslevel: - code = ( - "def %(name)s%(grouped_args)s:\n" - " return target_cls.%(name)s(%(apply_kw_proxied)s)" - % metadata - ) - env["target_cls"] = target_cls - else: - code = ( - "def %(name)s%(grouped_args)s:\n" - " return %(self_arg)s._proxied.%(name)s(%(apply_kw_proxied)s)" # noqa: E501 - % metadata - ) - - proxy_fn = cast( - types.FunctionType, _exec_code_in_env(code, env, fn.__name__) - ) - proxy_fn.__defaults__ = getattr(fn, "__func__", fn).__defaults__ - proxy_fn.__doc__ = inject_docstring_text( - fn.__doc__, - ".. container:: class_bases\n\n " - "Proxied for the %s class on behalf of the %s class." - % (target_cls_sphinx_name, proxy_cls_sphinx_name), - 1, - ) - - if clslevel: - return classmethod(proxy_fn) - else: - return proxy_fn - - def makeprop(name): - attr = target_cls.__dict__.get(name, None) - - if attr is not None: - doc = inject_docstring_text( - attr.__doc__, - ".. container:: class_bases\n\n " - "Proxied for the %s class on behalf of the %s class." - % ( - target_cls_sphinx_name, - proxy_cls_sphinx_name, - ), - 1, - ) - else: - doc = None - - code = ( - "def set_(self, attr):\n" - " self._proxied.%(name)s = attr\n" - "def get(self):\n" - " return self._proxied.%(name)s\n" - "get.__doc__ = doc\n" - "getset = property(get, set_)" - ) % {"name": name} - - getset = _exec_code_in_env(code, {"doc": doc}, "getset") - - return getset - - for meth in methods: - if hasattr(cls, meth): - raise TypeError( - "class %s already has a method %s" % (cls, meth) - ) - setattr(cls, meth, instrument(meth)) - - for prop in attributes: - if hasattr(cls, prop): - raise TypeError( - "class %s already has a method %s" % (cls, prop) - ) - setattr(cls, prop, makeprop(prop)) - - for prop in classmethods: - if hasattr(cls, prop): - raise TypeError( - "class %s already has a method %s" % (cls, prop) - ) - setattr(cls, prop, instrument(prop, clslevel=True)) - return cls return decorate diff --git a/test/ext/asyncio/test_scoping_py3k.py b/test/ext/asyncio/test_scoping_py3k.py index d722320f3e..caba1c6600 100644 --- a/test/ext/asyncio/test_scoping_py3k.py +++ b/test/ext/asyncio/test_scoping_py3k.py @@ -37,8 +37,9 @@ class AsyncScopedSessionTest(AsyncFixture): await AsyncSession.flush() conn = await AsyncSession.connection() + stmt = select(func.count(User.id)).where(User.name == user_name) - eq_(await conn.scalar(stmt), 1) + eq_(await AsyncSession.scalar(stmt), 1) await AsyncSession.delete(u1) await AsyncSession.flush() diff --git a/tools/generate_proxy_methods.py b/tools/generate_proxy_methods.py new file mode 100644 index 0000000000..eec4d878ac --- /dev/null +++ b/tools/generate_proxy_methods.py @@ -0,0 +1,413 @@ +"""Generate static proxy code for SQLAlchemy classes that proxy other +objects. + +This tool is run at source code authoring / commit time whenever we add new +methods to engines/connections/sessions that need to be generically proxied by +scoped_session or asyncio. The generated code is part of what's committed +to source just as though we typed it all by hand. + +The original "proxy" class was scoped_session. Then with asyncio, all the +asyncio objects are essentially "proxy" objects as well; while all the methods +that are "async" needed to be written by hand, there's lots of other attributes +and methods that are proxied exactly. + +To eliminate redundancy, all of these classes made use of the +@langhelpers.create_proxy_methods() decorator which at runtime would read a +selected list of methods and attributes from the proxied class and generate new +methods and properties descriptors on the proxying class; this way the proxy +would have all the same methods signatures / attributes / docstrings consumed +by Sphinx and look just like the proxied class. + +Then mypy and typing came along, which don't care about runtime generated code +and never will. So this script takes that same +@langhelpers.create_proxy_methods() decorator, keeps its public interface just +as is, and uses it to generate all the code and docs in those proxy classes +statically, as though we sat there and spent seven hours typing it all by hand. +The runtime code generation part is removed from ``create_proxy_methods()``. +Now we have static code that is perfectly consumable by all the typing tools +and we also reduce import time a bit. + +A similar approach is used in Alembic where a dynamic approach towards creating +alembic "ops" was enhanced to generate a .pyi stubs file statically for +consumption by typing tools. + +.. versionadded:: 2.0 + +""" +from __future__ import annotations + +from argparse import ArgumentParser +import collections +import importlib +import inspect +import os +from pathlib import Path +import re +import shlex +import shutil +import subprocess +import sys +from tempfile import NamedTemporaryFile +import textwrap +from typing import Any +from typing import Callable +from typing import Dict +from typing import Iterable +from typing import TextIO +from typing import Tuple +from typing import Type +from typing import TypeVar + +from sqlalchemy import util +from sqlalchemy.util import compat +from sqlalchemy.util import langhelpers +from sqlalchemy.util.langhelpers import format_argspec_plus +from sqlalchemy.util.langhelpers import inject_docstring_text + +is_posix = os.name == "posix" + + +sys.path.append(str(Path(__file__).parent.parent)) + + +class _repr_sym: + __slots__ = ("sym",) + + def __init__(self, sym: str): + self.sym = sym + + def __repr__(self) -> str: + return self.sym + + +classes: collections.defaultdict[ + str, Dict[str, Tuple[Any, ...]] +] = collections.defaultdict(dict) + +_T = TypeVar("_T", bound="Any") + + +def create_proxy_methods( + target_cls: Type[Any], + target_cls_sphinx_name: str, + proxy_cls_sphinx_name: str, + classmethods: Iterable[str] = (), + methods: Iterable[str] = (), + attributes: Iterable[str] = (), +) -> Callable[[Type[_T]], Type[_T]]: + """A class decorator that will copy attributes to a proxy class. + + The class to be instrumented must define a single accessor "_proxied". + + """ + + def decorate(cls: Type[_T]) -> Type[_T]: + # collect the class as a separate step. since the decorator + # is called as a result of imports, the order in which classes + # are collected (like in asyncio) can't be well controlled. however, + # the proxies (specifically asyncio session and asyncio scoped_session) + # have to be generated in dependency order, so run them in order in a + # second step. + classes[cls.__module__][cls.__name__] = ( + target_cls, + target_cls_sphinx_name, + proxy_cls_sphinx_name, + classmethods, + methods, + attributes, + cls, + ) + return cls + + return decorate + + +def process_class( + buf: TextIO, + target_cls: Type[Any], + target_cls_sphinx_name: str, + proxy_cls_sphinx_name: str, + classmethods: Iterable[str], + methods: Iterable[str], + attributes: Iterable[str], + cls: Type[Any], +): + + sphinx_symbol_match = re.match(r":class:`(.+)`", target_cls_sphinx_name) + if not sphinx_symbol_match: + raise Exception( + f"Couldn't match sphinx class identifier from " + f"target_cls_sphinx_name f{target_cls_sphinx_name!r}. Currently " + 'this program expects the form ":class:`_.`"' + ) + + sphinx_symbol = sphinx_symbol_match.group(1) + + def instrument(buf: TextIO, name: str, clslevel: bool = False) -> None: + fn = getattr(target_cls, name) + spec = compat.inspect_getfullargspec(fn) + + iscoroutine = inspect.iscoroutinefunction(fn) + + if spec.defaults: + new_defaults = tuple( + _repr_sym("util.EMPTY_DICT") if df is util.EMPTY_DICT else df + for df in spec.defaults + ) + elem = list(spec) + elem[3] = tuple(new_defaults) + spec = compat.FullArgSpec(*elem) + + caller_argspec = format_argspec_plus(spec, grouped=False) + + metadata = { + "name": fn.__name__, + "async": "async " if iscoroutine else "", + "await": "await " if iscoroutine else "", + "apply_pos_proxied": caller_argspec["apply_pos_proxied"], + "target_cls_name": target_cls.__name__, + "apply_kw_proxied": caller_argspec["apply_kw_proxied"], + "grouped_args": caller_argspec["grouped_args"], + "self_arg": caller_argspec["self_arg"], + "doc": textwrap.indent( + inject_docstring_text( + fn.__doc__, + textwrap.indent( + ".. container:: class_bases\n\n" + f" Proxied for the {target_cls_sphinx_name} " + "class on \n" + f" behalf of the {proxy_cls_sphinx_name} " + "class.", + " ", + ), + 1, + ), + " ", + ).lstrip(), + } + + if clslevel: + code = ( + "@classmethod\n" + "%(async)sdef %(name)s%(grouped_args)s:\n" + ' r"""%(doc)s\n """ # noqa: E501\n\n' + " return %(await)s%(target_cls_name)s.%(name)s(%(apply_kw_proxied)s)\n\n" # noqa: E501 + % metadata + ) + else: + code = ( + "%(async)sdef %(name)s%(grouped_args)s:\n" + ' r"""%(doc)s\n """ # noqa: E501\n\n' + " return %(await)s%(self_arg)s._proxied.%(name)s(%(apply_kw_proxied)s)\n\n" # noqa: E501 + % metadata + ) + + buf.write(textwrap.indent(code, " ")) + + def makeprop(buf: TextIO, name: str) -> None: + attr = target_cls.__dict__.get(name, None) + + return_type = target_cls.__annotations__.get(name, "Any") + assert isinstance(return_type, str), ( + "expected string annotations, is from __future__ " + "import annotations set up?" + ) + + if attr is not None: + if isinstance(attr, property): + readonly = attr.fset is None + elif isinstance(attr, langhelpers.generic_fn_descriptor): + readonly = True + else: + readonly = not hasattr(attr, "__set__") + doc = textwrap.indent( + inject_docstring_text( + attr.__doc__, + textwrap.indent( + ".. container:: class_bases\n\n" + f" Proxied for the {target_cls_sphinx_name} " + "class \n" + f" on behalf of the {proxy_cls_sphinx_name} " + "class.", + " ", + ), + 1, + ), + " ", + ).lstrip() + else: + readonly = False + doc = ( + f"Proxy for the :attr:`{sphinx_symbol}.{name}` " + "attribute \n" + f" on behalf of the {proxy_cls_sphinx_name} " + "class.\n" + ) + + code = ( + "@property\n" + "def %(name)s(self) -> %(return_type)s:\n" + ' r"""%(doc)s\n """ # noqa: E501\n\n' + " return self._proxied.%(name)s\n\n" + ) % {"name": name, "doc": doc, "return_type": return_type} + + if not readonly: + code += ( + "@%(name)s.setter\n" + "def %(name)s(self, attr: %(return_type)s) -> None:\n" + " self._proxied.%(name)s = attr\n\n" + ) % {"name": name, "doc": doc, "return_type": return_type} + + buf.write(textwrap.indent(code, " ")) + + for meth in methods: + instrument(buf, meth) + + for prop in attributes: + makeprop(buf, prop) + + for prop in classmethods: + instrument(buf, prop, clslevel=True) + + +def process_module(modname: str, filename: str) -> str: + + class_entries = classes[modname] + + # use tempfile in same path as the module, or at least in the + # current working directory, so that black / zimports use + # local pyproject.toml + with NamedTemporaryFile( + mode="w", delete=False, suffix=".py", dir=Path(filename).parent + ) as buf, open(filename) as orig_py: + + in_block = False + current_clsname = None + for line in orig_py: + m = re.match(r" # START PROXY METHODS (.+)$", line) + if m: + current_clsname = m.group(1) + args = class_entries[current_clsname] + sys.stderr.write( + f"Generating attributes for class {current_clsname}\n" + ) + in_block = True + buf.write(line) + buf.write( + "\n # code within this block is " + "**programmatically, \n" + " # statically generated** by" + " tools/generate_proxy_methods.py\n\n" + ) + + process_class(buf, *args) + if line.startswith(f" # END PROXY METHODS {current_clsname}"): + in_block = False + + if not in_block: + buf.write(line) + return buf.name + + +def console_scripts( + path: str, options: dict, ignore_output: bool = False +) -> None: + + entrypoint_name = options["entrypoint"] + + for entry in compat.importlib_metadata_get("console_scripts"): + if entry.name == entrypoint_name: + impl = entry + break + else: + raise Exception( + f"Could not find entrypoint console_scripts.{entrypoint_name}" + ) + cmdline_options_str = options.get("options", "") + cmdline_options_list = shlex.split(cmdline_options_str, posix=is_posix) + [ + path + ] + + kw = {} + if ignore_output: + kw["stdout"] = kw["stderr"] = subprocess.DEVNULL + + subprocess.run( + [ + sys.executable, + "-c", + "import %s; %s.%s()" % (impl.module, impl.module, impl.attr), + ] + + cmdline_options_list, + cwd=Path(__file__).parent.parent, + **kw, + ) + + +def run_module(modname, stdout): + + sys.stderr.write(f"importing module {modname}\n") + mod = importlib.import_module(modname) + filename = destination_path = mod.__file__ + assert filename is not None + + tempfile = process_module(modname, filename) + + ignore_output = stdout + + console_scripts( + str(tempfile), + {"entrypoint": "zimports"}, + ignore_output=ignore_output, + ) + + console_scripts( + str(tempfile), + {"entrypoint": "black"}, + ignore_output=ignore_output, + ) + + if stdout: + with open(tempfile) as tf: + print(tf.read()) + os.unlink(tempfile) + else: + sys.stderr.write(f"Writing {destination_path}...\n") + shutil.move(tempfile, destination_path) + + +def main(args): + from sqlalchemy import util + from sqlalchemy.util import langhelpers + + util.create_proxy_methods = ( + langhelpers.create_proxy_methods + ) = create_proxy_methods + + for entry in entries: + if args.module in {"all", entry}: + run_module(entry, args.stdout) + + +entries = [ + "sqlalchemy.orm.scoping", + "sqlalchemy.ext.asyncio.engine", + "sqlalchemy.ext.asyncio.session", + "sqlalchemy.ext.asyncio.scoping", +] + +if __name__ == "__main__": + parser = ArgumentParser() + parser.add_argument( + "--module", + choices=entries + ["all"], + default="all", + help="Which file to generate. Default is to regenerate all files", + ) + parser.add_argument( + "--stdout", + action="store_true", + help="Write to stdout instead of saving to file", + ) + args = parser.parse_args() + main(args)